Chemistry 105 Exam 1 Homework-Monte Helm

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Neutral atoms that gain electrons become __________. Select the correct answer below: A. neutrons B. protons C. anions D. cations

C. anions.

An object has a mass of 25.0 g and displaces 42.5 mL of water. What is the density of the object, in grams per milliliter?

0.588 g/mL

The Lewis symbol for sodium will have how many dots?

1 dot. With one valence electron, its Lewis symbol will have one dot.

Convert 3.00Cal into joules. Remember that 1Cal=1kcal=1,000cal. Your answer should have 3 significant figures.

1.26x10^4. Explanation: Convert Calories to calories and then to joules. 1.00Cal=1.00×10^3cal 1.00cal=4.184J 3.00Cal=3.00×10^3cal 3.00×10^3cal×4.184Jcal=12.552×103J=1.2552×10^4J The answer should have three significant figures, so round to 1.26×104J.

What is the density of a 37.2 mL sample of sulfuric acid weighing 63.8 g, in grams per milliliter?

1.71 g/mL

What is the difference in the number of electrons between the calcium ion and elemental calcium?

2 electrons. Explanation: Calcium ions are required for proper muscle and nerve function and are an important component of bones. A neutral calcium atom has 20 protons and 20 electrons. It loses 2 electrons to become a calcium ion and is symbolized as Ca2+.

The nutritional energy content (in Calories) present in 86g of broccoli with 6g of carbohydrates, 2.6g of protein, and 0.3g of fat is __________.

35 Calories. Explanation: First, calculate the Calories provided by individual macronutrients. 6 g carb×4Cal/g carb2.6 g protein×4Cal/g protein0.3 g fat×9Cal/g fat=24Cal=10.4Cal=2.7Cal Then, add these together: 24+10.4+2.7=37.1Cal Finally, round to the nearest 5 to give an answer of 35Calories.

Complete the following operation to the correct number of significant figures: 4.5×11.41= _________.

51. Explanation: When we multiply or divide, our answer should have the same number of significant figures as the number with the fewest significant figures. In this case, the number with the fewest significant figures is 4.5, so our answer should have two significant figures. To round 51.345 to two significant figures, round to the nearest whole number. Round down because the next digit is a 3. The answer with the correct number of significant figures is 51.

The Lewis symbol for the chloride ion will have how many dots?

8. Explanation: If a chlorine atom gains an electron to become the chloride ion, it will have 8 valence electrons and a full valence shell. This means its Lewis symbol will have 8 dots.

Which best describes the dipole-dipole attractions? They are specifically the interaction between_______. Select the correct answer below: A. two formal, or permanent, dipoles B. an instantaneous dipole and a formal dipole C. two temporary dipoles D. none of the above

A. two formal, or permanent, dipoles.

What is the density of water? Select the correct answer below: A. 0.001g/cm^3 B. 0.11g/cm^3 C. 1.0g/cm^3 D. 10g/cm^3

C. 1.0g/cm^3

Which two subatomic particles would have a combined unit charge of 0? Select the correct answer below: A. proton, neutron B. proton, positron C. neutron, electron D. electron, proton

D. electron, proton. Explanation: Two subatomic particles that when combined have a 0 net charge are the electron (−1) and the proton (+1).

Identify the chemical symbol of mercury.

Hg. Mercury is located in group 12 of the periodic table.

What is the chemical symbol for the element potassium?

K. This can be found in group 1 of the periodic table.

Identify the chemical symbol for krypton.

Kr. Explanation: The chemical symbol for krypton is Kr. Krypton is located in group 18 in the periodic table.

What is the chemical symbol for the element zinc?

Zn. This is located in group 12 of the periodic table.

Which of the following would have the higher boiling point? Select the correct answer below: a. CH3CHO b. F2 C. they have the same boiling point D. there is not enough information to determine this

a. CH3CHO. Explanation: Compounds with stronger intermolecular forces will have higher boiling points (ion ion > hydrogen bonding > dipole dipole > london dispersion). F2 is nonpolar and only has dispersion forces. CH3CHO is polar and has dipole-dipole attractions so it will have the higher boiling point.

How many electrons does O^2− contain?

10 electrons. Explanation: The following equation can be used to determine the number of electrons in an element. overall charge=number of protons−number of electrons. The overall charge of the ion is −2. Rearranging and using the atomic number for the number of protons, we can solve for the number of electrons: number of electrons=number of protons−overall charge. number of electrons=8−(−2)=10

How many electrons does O^2− contain?

10 electrons. Explanation: The following equation can be used to determine the number of electrons in an element: Overall charge=number of protons−number of electrons. The overall charge of the ion is −2. Rearranging and using the atomic number for the number of protons, we can solve for the number of electrons: Number of electrons=number of protons−overall charge. number of electrons=8−(−2)=10.

How many electrons does Na+ contain?

10 electrons. Explanation: The following equation can be used to determine the number of electrons in an element: overall charge=number of protons−number of electrons. The overall charge of the ion is +1. Rearranging and using the atomic number for the number of protons, we can solve for the number of electrons: # of electrons=number of protons−overall charge. # of electrons= 11−(+1)=10.

Find the number of protons, neutrons, and electrons in 27/13Al.

13 protons, 14 neutrons, and 13 electrons. Explanation: Start by using the atomic number from the symbol 27/13Al to find the number of protons. The 13 in the lower left is the atomic number, which means it is also the number of protons. In an uncharged atom, the number of protons matches the number of electrons, so there are also 13 electrons. The mass number is written in the upper left corner and is equal to the number of protons and neutrons. Writing the equation and solving for the number of neutrons gives mass number: number of neutrons=number of protons+number of neutrons= mass #−number of protons=27−13=14. Therefore, 27/13Al has 13 protons, 14 neutrons, and 13 electrons.

Write the atomic symbol (including the atomic number) for an isotope with 54 protons and 78 neutrons. Write the answer in the form XZA using the atomic symbol button in the toolbar, where A is the mass number, Z is the atomic number, and X is the chemical symbol for the unknown element.

132/54Xe. Explanation: An isotope with 54 protons and 78 neutrons has an atomic number of 54 and a mass number of 54+78=132. Look up the atomic number on the periodic table to find the elemental symbol, Xe. The atomic symbol is written with the atomic number on the lower left and the mass number on the upper left, so it is 132/54Xe.

Write the atomic symbol (including the atomic number) for the isotope of neodymium with 90 neutrons. Write the answer in the form XZA using the atomic symbol button in the toolbar, where A is the mass number, Z is the atomic number, and X is the chemical symbol for the unknown element.

150/60 Nd. Explanation: Using the periodic table to find "neodymium," the symbol is Nd and the atomic number is 60, which is also the number of protons. An isotope with 60 protons and 90 neutrons has mass number of 60+90=150. The atomic symbol is written with the atomic number on the lower left and the mass number on the upper left, so it is 150/60Nd.

Write the atomic symbol (including the atomic number) for an isotope with 64 protons and 96 neutrons.

160/64Gd. Explanation: An isotope with 64 protons and 96 neutrons has an atomic number of 64 and a mass number of 64+96=160. Look up the atomic number on the periodic table to find the elemental symbol, Gd. The atomic symbol is written with the atomic number on the lower left and the mass number on the upper left, so it is 160/64Gd.

What is the difference in the number of electrons between the magnesium ion and elemental magnesium?

2 electrons. Explanation: Magnesium ions are an important component of bone and required for nerve control. In a magnesium atom, there are 12 electrons, making the atom neutral. When an ion is formed, the magnesium atom loses 2 electrons. Therefore, the magnesium ion has 2 more protons than electrons. It is symbolized as Mg2+

Find the number of protons, neutrons, and electrons in 40/20Ca.

20 protons, 20 neutrons, and 20 electrons. Explanation: Start by using the atomic number from the symbol 40/20Ca to find the number of protons. The 20 in the lower left is the atomic number, which means it is also the number of protons. In an uncharged atom, the number of protons matches the number of electrons, so there are also 20 electrons. The mass number is written in the upper left corner and is equal to the number of protons and neutrons. Mass number=protons+neutrons (40-20=20). Number of neutrons=mass number-protons.

How many neutrons are in the isotope 37Cl? (HINT: the 37 refers to the mass number of the isotope). Report your answer as a whole number without decimal places.

20. neutrons. Explanation: You can use the equation below to calculate the number of neutrons in an atom. Mass number−Number of protons=Number of neutrons. The mass number of the isotope (37) is given. We can read the atomic number of Cl from the periodic table to find that this element has 17 protons. Using these two values, we can calculate the number of neutrons. 37−17=20

A strawberry weighing 12 grams contains 4 Cal of nutritional energy. How many strawberries should a person consume to get 100 Cal of energy?

25 strawberries. 100 Cal/4Cal=25.

Determine the number of electrons in an atom of manganese.

25. Explanation: Since the atom has a neutral charge the number of protons is equal to the number of electrons. Therefore, we can see from the atomic number that an atom of manganese has 25 electrons.

Find the number of protons, neutrons, and electrons in 64/29Cu.

29 protons, 35 neutrons, and 29 electrons. Explanation: Start by using the atomic number from the symbol 64/29Cu to find the number of protons. The 29 in the lower left is the atomic number, which means it is also the number of protons. In an uncharged atom, the number of protons matches the number of electrons, so there are also 29 electrons. The mass number is written in the upper left corner and is equal to the number of protons and neutrons. Writing the equation and solving for the number of neutrons gives the mass number: number of neutrons=number of protons+number of neutrons=mass number−number of protons=64−29=35 Therefore, 64/29Cu has 29 protons, 35 neutrons, and 29 electrons.

Calculate the Caloric content present in 100g of brown bread. It contains 54g of carbohydrates, 11g of protein, and 3.3g of fat. Round your answer to the nearest 10.

290 Calories. Explanation: First calculate the Calories provided by individual macronutrients. 54 grams of carb×4 Cal/gram of carb= 216 Cal 11 grams of protein x 4 Cal/grams of protein= 44 Cal 3.3 grams of fat x 9Cal/gram of fat= 29.7 Cal Then add them together: 216+44+29.7=289.7 Cal. Round to the nearest 10 to give the final answer of 290 Cal.

There are 200 tomatoes in a bushel. If an average tomato contains about 0.20g fat, 1.1g protein, and 4.8g carbohydrate, how many Calories are in 7 bushels of average-sized tomatoes? Round your answer to two significant figures.

36000 Calories. Explanation: To find the Caloric content, use the average values of 4 Calories per gram for carbohydrates, 4 Calories per gram for proteins, and 9 Calories per gram for fat. First find the Caloric content in one tomato, and then multiply by the number of tomatoes in a bushel, 200, and the number of bushels, 7. 1.1 gram protein×4 Calories per gram of protein+4.8 gram of carb×4 Calories per gram of carb+0.2 gram of fat×9 Calories per gram of fat=25.4 Calories. 25.4 Calories per tomato×200 tomatoes per bushel×7 bushels=35,560 Calories, which rounds to36,000 Calories.

Determine the number of neutrons in the isotope bromine-81.

46 neutrons. Explanation: The following equation can be used to determine the number of neutrons in an element. mass number=number of protons+number of neutrons. Rearranging and using the atomic number for the number of protons, we can solve for the number of neutrons: number of neutrons=mass number−number of protons. number of neutrons=81−35=46

Find the number of protons, neutrons, and electrons in 133/55Cs.

55 protons, 78 neutrons, 55 electrons. Explanation: Start by using the atomic number from the symbol 13355Cs to find the number of protons. The 55 in the lower left is the atomic number, which means it is also the number of protons. In an uncharged atom, the number of protons matches the number of electrons, so there are also 55 electrons. The mass number is written in the upper left corner and is equal to the number of protons and neutrons. Mass number= protons+neutrons. Number of neutrons= mass number-protons (133-55=78). Therefore, 133/55Cs has 55 protons, 78 neutrons, and 55 electrons.

A star has a radius of about 84,000,000meters. Write this value in scientific notation.

8.4 x 10^7. Explanation: Because the magnitude of this number is greater than 1, the exponent will be positive. Move the decimal point to the left until the number has a single digit in the ones place. In this case, the decimal point is moved 7 places to the left to get the number 8.4, and this means the exponent is 7. Therefore, 84,000,000=8.4×107.

The nutritional information for a 100g package of shredded, hard-boiled egg states that it has 14g of protein, 1g of carbohydrates, and 11g of fat. How many Calories would you expect to find in a single 50g egg?Round your answer to the nearest 10.

80 Calories. Explanation: First calculate the Calories provided by the individual macronutrients: 1g carb×4Cal/g carb=4Cal 14g protein×4Cal/g protein=56Cal 11g fat×9Cal/g fat=99Cal Add the energy of each component to find the total nutritional energy in the 100g serving. 4Cal+56Cal+99Cal=159Cal So there are about 159Cal per 100g of egg. Write this as a conversion factor and multiply by 50g egg to find the energy in a single egg. 50g egg×159Cl/100g egg=79.5Cal Finally, rounding to the nearest 10 gives 80Calories.

In the ionic compound, Ba(NO3)2, what is the charge of the cation? Select the correct answer below: A. 2+ B. 2− C. 3+ D. 3−

A. 2+. Explanation: The cation is barium. If you look on the periodic chart, barium is in the second column. Each of the elements in this column has 2 valence (outer shell) electrons which means they would carry a 2+ charge when combining with an anion.

The modern periodic table is organized into __________________. Select the correct answer below: A. 7 periods and 18 groups B. 18 periods and 7 groups C. 4 periods and 14 groups D. 14 periods and 14 groups

A. 7 periods and 18 groups. Explanation: The elements in the periodic table are arranged into 7 horizontal rows known as periods or series, and 18 vertical columns, called groups. Groups are labeled at the top of each column.

The most common isotope of nitrogen has a mass number of 14. Identify the number of neutrons in this isotope. Select the correct answer below: A. 7 B. 7.01 C. 14.01 D. 14

A. 7. Explanation: The atomic number is 7, which represents the number of protons. The average atomic mass is 14.01, but individual isotopes can only have whole numbers of neutrons. The mass number, 14, is the number of protons plus the number of neutrons, so there are exactly 7 neutrons in each atom of the isotope.

Which of the following is the chemical symbol for carbon monoxide? The carbon monoxide compound contains one carbon and one oxygen atom. Select the correct answer below: A. CO B. co C. Co D. cO

A. CO. Explanation: Carbon monoxide is a compound, meaning it is made of more than one element. The chemical symbol for carbon monoxide is CO. co and cO are not valid chemical symbols. Co is the chemical symbol for the element cobalt.

How does the chloride ion Cl− differ from elemental chlorine? Select the correct answer below: A. Chloride ion has 1 electron more than elemental chlorine. B. Chloride ion has 1 electron less than elemental chlorine. C. Chloride ion has 2 electrons more than elemental chlorine . D. Chloride ion has 2 electrons less than elemental chlorine.

A. Chloride ion has 1 electron more than elemental chlorine. Explanation: The chloride ion has a negative charge, so it cannot have LESS electrons than elemental chlorine.

Which of the following is a correct method for determining the number of neutrons in an atomic nucleus? Select the correct answer below: A. The mass number is equal to the number of neutrons. B. Subtract the atomic number from the mass number. C. Add the atomic number and the mass number. D. Determine the number of protons; the number of neutrons is always equal to the number of protons in an atomic nucleus.

B. Subtract the atomic number from the mass number. Explanation: Since the number of neutrons plus the number of protons is equal to the mass number in an atomic nucleus, subtract the atomic number (which is the same as the number of protons) from the mass number to obtain the number of neutrons. Mass number−atomic number=number of neutrons.

What subatomic particle is characterized by a negative charge? Select the correct answer below: A. electron B. neutron C. proton D. positron

A. electron. Explanation: Electrons are found outside of the nucleus and are characterized by a negative charge. The nucleus contains the majority of an atom's mass because protons and neutrons are much heavier than electrons, whereas electrons occupy almost all of an atom's volume.

Which type of nutrient provides the most energy per gram? Select the correct answer below: A. fats B. protein C. carbohydrates D. These are all equivalent

A. fats. Explanation: Fats and oils provide around 9 Calories per gram, while proteins and carbohydrates only provide around 4.

Which of the following is a property of an ionic compound? Select the correct answer below: A. high melting point B. soft C. malleable D. liquid at room temperature

A. high melting point. Explanation: Most ionic compounds are solids that typically melt at high temperatures and boil at even higher temperatures. None of the other options apply.

Where are neutrons located? Select the correct answer below: A. inside the nucleus B. outside the nucleus C. underneath the nucleus D. none of the above

A. inside the nucleus. Explanation: The neutrally charged neutrons are located inside the nucleus. Positively charged protons are also found inside the nucleus which is surrounded by a much larger volume of space containing negatively charged electrons.

A __________ contains more than one type of substance as part of its composition. Select the correct answer below: A. mixture B. pure substance C. compound D. element

A. mixture. Explanation: A mixture contains more than one type of element or compound. A mixture can be categorized as homogeneous or heterogeneous depending on whether it has a uniform composition or not.

When a neutral atom gains an electron, it will have a Select the correct answer below: A. negative charge. B. positive charge. C. neutral charge. D. reduced mass.

A. negative charge. Explanation: Any time the number of electrons and protons in an atom are not equal, the atom will not be neutral (it will be charged: an ion).

When an atom gains electrons, it becomes a __________. Select the correct answer below: A. negatively charged ion, known as an anion B. negatively charged ion, known as a cation C. positively charged ion, known as an anion D. positively charged ion, known as a cation

A. negatively charged ion, known as an anion. Explanation: Electrons are negatively charged. When an atom gains electrons, it becomes negatively charged and is referred to as an anion. When an atom loses electrons, it becomes positively charged and is referred to as a cation.

Covalent bonds are most commonly formed between: Select the correct answer below: A. nonmetals B. metals C. a metal and a nonmetal D. a metal and a metalloid

A. nonmetals. Explanation: Bonds between nonmetals are almost always covalent in nature.

When a pure substance undergoes a change from a solid state to a gaseous state, this is an example of a(n): Select the correct answer below: A. physical change B. chemical change C. electrical change D. reactive change

A. physical change. Explanation: When a pure substance undergoes a change from a solid state to a gaseous state, this is an example of a physical change. This is because the chemical formula that describes a pure substance does not change during a change of state.

Which particle is NOT part of most atoms? Select the correct answer below: A. positron B. proton C. neutron D. electron

A. positron. Explanation: The positron is an antimatter particle, whereas the other three options are found in all atomic matter.

Which of the following does not belong to the noble gases? Select the correct answer below: A. potassium B. neon C. argon D. helium

A. potassium. Explanation: Potassium belongs to the alkali metals and not the noble gases.

Which two particles have roughly the same mass? Select the correct answer below: A. proton and neutron B. proton and electron C. neutron and electron D. atom and neutron

A. proton and neutron. Explanation: The proton and neutron both have a mass of roughly 1.67×10^−24 grams.

The number of __________ in an atom is automatically known if the element is specified. Select the correct answer below: A. protons B. neutrons C. electrons D. none of the above

A. protons. Explanation: Every element has a characteristic number of protons in the nucleus. So if one knows the type of element, one must also know the number of protons in the nucleus.

What is another word for period? Select the correct answer below: A. series B. group C. section D. family

A. series. Explanation: A period is also referred to as a series. The period, or series, groups elements based on their atomic orbitals.

NaCl has the chemical name of __________. Select the correct answer below: A. sodium chloride B. sodium chlorine C. sodide chlorine D. sodide chloride

A. sodium chloride.

Which phase exhibits the strongest intermolecular forces? Select the correct answer below: A. solids B. liquids C. gases D. these will all exhibit the same degree of interaction

A. solids. Explanation: In a solid, particles are in constant contact and fixed positions that will maximize intermolecular forces.

The symbol for a specific isotope of any element is written by placing the mass number as a ______________________ of the element symbol. Select the correct answer below: A. superscript to the left B. superscript to the right C. subscript to the left D. subscript to the right

A. superscript to the left. The symbol for a specific isotope of any element is written by placing the mass number as a superscript to the left of the element symbol. The atomic number is sometimes written as a subscript preceding the symbol, but since this number defines the element's identity, as does its symbol, it is often omitted.

When naming an ionic compound consisting of monoatomic ions, which ion will be listed first? Select the correct answer below: A. the cation B. the anion C. the ion with smaller magnitude of charge D. the ion with greater magnitude of charge

A. the cation. Explanation: By convention, we always list the cation first. For example, the compound sodium chloride (NaCl) is an ionic compound consisting of monoatomic ions. The cation is the sodium ion (Na+) which appears in the name before the chloride anion (Cl−).

Hydrogen bonding is responsible for___. Select the correct answer below: A. the unexpectedly high boiling points for hydrides in period two. B. the increasing boiling points for hydrides going down a group C. the low boiling points of nonpolar molecules D. none of the above

A. the unexpectedly high boiling points for hydrides in period two. Explanation: The boiling points for water, ammonia, and hydrogen fluoride defy the linear trend put forth by other hydrides in their groups. Their hydrogen bonding causes them to boil at much higher temperatures than expected.

Change 9.46×10−6 into standard notation. Select the correct answer below: A. 9,460,000 B. 0.00000946 C. 9.46 D. 0.000000946

B. 0.00000946. Explanation: Scientific notation is used to express very large and very small numbers as a product of two numbers. The first number of the product is usually a number not less than 1 and not greater than 10. The second number of the product, the exponential term, is written as 10 with an exponent. To convert 9.46×10−6 into standard notation move the decimal point to the left six place values to get 0.00000946.

1 Calorie is defined as the amount of energy required to heat __________. Select the correct answer below: A. 1g of water by 1∘C B. 1kg of water by 1∘C C. 1kg of water by 100∘C D. 1g of water by 100∘C

B. 1 kg of water by 1∘C. Explanation: The measure of energy required to heat 1kg of water by 1∘C is 1Calorie. Note that Calorie is capitalized. When the unit used is calorie (in lower case), it is the energy required to heat 1g of water by 1∘C.

How many electrons does potassium need to lose to attain a noble gas configuration? Select the correct answer below: A. 5 B. 1 C. 3 D. 8

B. 1. Explanation: Metal atoms of the elements in group 1 and group 2 lose enough electrons to leave them with the same number of electrons as an atom of the preceding noble gas. Potassium (K) is in group 1 and needs to lose 1 electron to attain a noble gas configuration.

What is the atomic symbol for an atom with 72 protons, 108 neutrons, and 72 electrons? Select the correct answer below: A. 108/72Hs B. 180/72Hf C. 180/108Hs D. 108/72Hf

B. 180/72Hf. Explanation: The atomic number is the number of protons, or 72. By referring to the periodic table, we can find the symbol for the element, Hf. Find the mass number by adding the number of protons to the number of neutrons: mass number=number of protons+number of neutrons=72+108=180. Write the atomic symbol by writing the element symbol first and then writing the atomic number in the lower left and the mass number in the upper left. Therefore, the symbol is 180/72Hf.

Elements in group 2 will tend to form ions with a charge of __________. Select the correct answer below: A. 1+ B. 2+ C. 1− D. 2−

B. 2+. Explanation: Elements in group 2 will have a tendency to lose two electrons, giving them a charge of 2+.

Molecular compounds must contain a minimum of how many atoms? Select the correct answer below: A. 1 B. 2 C. 3 D. 4

B. 2. Explanation: A molecular compound requires at least one covalent bond, and a covalent bond occurs between two atoms, so a molecular compound must have at least two atoms.

What is the formula of the ionic compound formed between the cation, Ca2+, and the anion, phosphate, PO3−4? Select the correct answer below: A. Ca(PO4)2 B. Ca3(PO4)2 C. Ca3PO4 D. CaPO4

B. Ca3(PO4)2. Explanation: Because the ionic compound must be electrically neutral, it must have the same number of positive and negative charges. Three calcium ions, each with a charge of 2+, would give us six positive charges, and 2 phosphate ions with a charge of 3−, would give us six negative charges.

Knowing that electronegativity increases going up and to the right on the periodic table, which molecule would you expect to have the strongest dipole-dipole interactions?Select the correct answer below: A. HCl B. HBr C. HI D. HAt

A. HCl. Explanation: The elements bound to H are all in the same group (column) on the periodic table. Among the choices, Cl is the element that is the highest in the group, therefore, HCl will have the strongest dipole out of these options, resulting in the strongest dipole-dipole interactions.

Which of the following molecules will NOT participate in dipole-dipole interactions? Select the correct answer below: A. SO2 B. H2O C. H2S D. CO2

D. CO2. Explanation: Only molecules with an overall net dipole will be able to participate in dipole-dipole interactions. Therefore, of the choices given only CO2 is a nonpolar molecule with no net dipole. Even though it does have polar bonds, the dipoles point in opposite directions and cancel each other out making it a nonpolar molecule that exhibits only London dispersion forces.

Name the ion that acts as the cofactor of chlorophyll in green plants and is needed for nerve control. Select the correct answer below: A. CO2−3 B. Na+ C. Fe2+ D. Mg2+

D. Mg2+. Explanation: Magnesium ions, Mg2+, are the cofactors in chlorophyll in green plants and are needed for nerve control.

Manganese(V) oxide is formed from Mn5+ cations and O2− anions. What will be its chemical formula? Select the correct answer below: A. 3Mn2O5 B. MnO3 C. 2MnO5 D. Mn2O5

D. Mn2O5. Explanation: An ionic compound must be electrically neutral, so it must have the same number of positive and negative charges. Two manganese cations, each with a charge of 5+, would give us ten positive charges, while five oxygen anions, each with a charge of 2−, would give us ten negative charges. Therefore, the formula would be Mn2O5.

What is the chemical formula for the polyatomic ion permanganate? Select the correct answer below: A. ClO−4 B. NO−3 C. PO3−4 D. MnO−4

D. MnO−4. Explanation: The chemical formula for permanganate is MnO−4. ClO−4 is the formula for perchlorate. NO−3 is the formula for nitrate. PO3−4 is the formula for phosphate.

Which of the following questions is most directly answered by using chemistry? Select the correct answer below: A. How fast does an airplane need to fly to stay up in the air? B. Why do apples slices turn brown? C. How big does the support beam for a deck need to be? D. Which way should you point a fan in a window during the summer?

B. Why do apples slices turn brown? Explanation: While some results from chemistry might be applicable to all these questions, the browning of an apple directly involves chemical reactions. So the principles of chemistry are required to understand what is happening.

What does each box in the periodic table represent? Select the correct answer below: A. a family B. an element C. a mass unit D. a period

B. an element. Explanation: Each box in the periodic table represents an element. In addition to the element symbol, each box contains an atomic weight, atomic number, and name that correspond with that element.

Identify a major source of carbonate ions. Select the correct answer below: A. oxygen B. carbon dioxide C. salt D. milk

B. carbon dioxide. Explanation: Carbon dioxide is a major source of carbonate ions, which make up a large amount of the ionic structure of bone. Salt is a source of sodium and chloride ions, milk is a source of calcium ions, and oxygen is an element.

What is the name of the binary compound: CF4? Select the correct answer below: A. carbon fluoride B. carbon tetrafluoride C. tetracarbon fluoride D. carbon fluorine

B. carbon tetrafluoride.

Which of the following is NOT a group on the periodic table? Select the correct answer below: A. noble gases B. carcinogens C. alkali metals D. halogens

B. carcinogens

ll of the following are chemical properties EXCEPT: Select the correct answer below: A. corrosiveness B. density C. water reactivity D. flammability

B. density. Explanation: Corrosiveness, water reactivity, and flammability are all examples of chemical properties. The density of a substance is considered a physical property.

Hydrogen bonding is technically a type of_____. Select the correct answer below: A. dispersion force B. dipole-dipole attraction C. ionic bond D. none of the above

B. dipole-dipole attraction. Explanation: Hydrogen bonds are exceptionally strong dipole-dipole interactions. Hydrogen bonding can occur when a molecule contains a hydrogen atom bonded to a fluorine, oxygen, or nitrogen atom (the three most electronegative elements). The very large difference in electronegativity between the H atom (2.1) and the atom to which it is bonded (4.0 for an F atom, 3.5 for an O atom, or 3.0 for an N atom), combined with the very small size of an H atom and the relatively small sizes of F, O, or N atoms, leads to highly concentrated partial charges with these atoms.

An ion results from an atom that gains or loses __________. Select the correct answer below: A. protons B. electrons C. neutrons D. orbitals

B. electrons.

Oil and water collected together in a container is an example of a: Select the correct answer below: A. homogeneous mixture B. heterogeneous mixture C. pure substance D. compound

B. heterogeneous mixture. Explanation: Oil and water are separate compounds and are not chemically bonded together. Therefore, together, they are not a pure substance or compound. In addition, oil and water will not mix evenly, so this is an example of a heterogenous mixture.

Orange juice with pulp is an example of a: Select the correct answer below: A. homogeneous mixture B. heterogeneous mixture C. pure substance D. compound

B. heterogeneous mixture. Explanation: This is not distributed evenly, as the pulp will clump together rather than completely spread out.

Compounds formed by a transfer of electrons are _____ compounds. Select the correct answer below: A. covalent B. ionic C. metallic D. nonmetallic

B. ionic. Explanation: The compound formed by a transfer of electrons is stabilized by the electrostatic attractions (ionic bonds) between the ions of opposite charge present in the compound.

The ion Na+ has a 1+ charge. This means this element has __________. Select the correct answer below: A. gained an electron B. lost an electron C. gained a proton D. lost a proton

B. lost an electron. Explanation: The ion Na+ occurs when neutral Na loses an electron. This is what gives it a 1+ charge. When an element loses an electron, it becomes a positive ion, and when it gains an electron, it become a negative ion.

Atoms of the same element can have different: Select the correct answer below: A. atomic numbers B. mass numbers C. numbers of protons D. none of the above

B. mass numbers. Explanation: Atoms of the same element must have the same number of protons, as this defines their atomic number which is characteristic of that element. But they may have differing numbers of neutrons which would generate a different mass number.

Which subatomic particle has no electric charge? Select the correct answer below: A. proton B. neutron C. electron D. they all have electric charge

B. neutron. Explanation: The proton is positively charged and the electron is negatively charged, while the neutron, as its name would suggest, has neutral charge, or no charge.

Which of the following pairings usually forms molecular compounds? Select the correct answer below: A. metal, nonmetal B. nonmetal, nonmetal C. metal, metal D. none of the above

B. nonmetal, nonmetal. Explanation: Molecular compounds are usually formed when a nonmetal bonds with another nonmetal.

Where are electrons located? Select the correct answer below: A. inside the nucleus B. outside the nucleus C. underneath the nucleus D. none of the above

B. outside the nucleus. Explanation: The negatively charged electrons are located outside the nucleus. The nucleus contains neutrally charged neutrons and positively charged protons.

What is the general name for polyatomic ions that contain one or more oxygen atoms? Select the correct answer below: A. oxides B. oxyanions C. hydroxides D. polyoxides

B. oxyanions. Explanation: Oxyanions are particularly common among polyatomic ions. Oxyanions are polyatomic ions that contain one or more oxygen atoms. Two specific oxyanions are peroxide, O2−2, and hydroxide, OH−.

What is the name for the binary compound: PCl3? Select the correct answer below: A. phosphorus trichlorine B. phosphorus trichloride C. monophosphorous chloride D. phosphorus chloride

B. phosphorus trichloride.

Which of the following particles is correctly matched with its charge and location (select all that apply)? Select all that apply: A. neutron: negative charge, within the nucleus B. proton: positive charge, within the nucleus C. electron: no charge, outside the nucleus D. electron: negative charge, outside the nucleus

B. proton: positive charge, within the nucleus, and D. electron: negative charge, outside the nucleus. Explanation: Atoms contain a very small nucleus composed of positively charged protons and uncharged neutrons, surrounded by a much larger volume of space containing negatively charged electrons.

Which of the following statements about bromine (Br) are true? Select all that apply: A. Bromine needs to gain 1 electron to achieve noble gas electron configuration. B. Bromine is a halogen. C. If bromine gains 18 electrons, it will have the same configuration as krypton. D. If bromine gains 1 electron, it will have the same electron configuration as argon.

Both A. Bromine needs to gain 1 electron to achieve noble gas electron configuration, and B. Bromine is a halogen. Explanation: Bromine is a halogen, so it needs to gain 1 electron to achieve noble gas electron configuration. If bromine gains 1 electron, it will have the same electron configuration as krypton, not argon.

If an atom has a mass number of 18 and an atomic number of 10, then how many protons and neutrons does it contain? Select the correct answer below: A. 8 protons, 10 neutrons B. 7 protons, 11 neutrons C. 10 protons, 8 neutrons D. 9 protons, 9 neutrons

C. 10 protons, 8 neutrons. Explanation: If the mass number is 18 and the atomic number is 10 (number of protons) then there are 10 protons and 8 neutrons (18−10=8).

Halogens will tend to form ions with a charge of __________. Select the correct answer below: A. 1+ B. 2+ C. 1− D. 2−

C. 1−. Explanation: The halogens have a tendency to gain one electron, giving them a charge of 1−.

The Lewis symbol for chlorine will have how many electrons? Select the correct answer below: A. 5 B. 6 C. 7 D. 8

C. 7. Explanation: Chlorine has seven valence electrons, so its Lewis symbol will have seven dots.

What is the atomic symbol for an atom with 38 protons, 48, neutrons and 38 electrons? Select the correct answer below: A. 48/38Rn B. 86/48Rn C. 86/38Sr D. 48/38Sr

C. 86/38Sr. Explanation: The atomic number is the number of protons, or 38. By referring to the periodic table, we can find the symbol for the element, Sr. Find the mass number by adding the number of protons to the number of neutrons: mass number= protons+neutrons (38+48=86). Write the atomic symbol by writing the element symbol first and then writing the atomic number in the lower left and the mass number in the upper left. Therefore, the symbol is 86/38Sr.

Which is the atomic mass of Strontium? Select the correct answer below: A. 38 amu B. 44.956 amu C. 87.62 amu D. 21 amu

C. 87.62 amu. Explanation: Strontium has an atomic mass of 87.62 amu. This value can be found at the bottom of the element block.

Molybdenum-99 is an isotope used to produce an isomer used in nuclear medicine. What is the atomic symbol for molybdenum-99? Select the correct answer below: A. 57/42Mo B. 99/57Mo C. 99/42Mo D. 99/25Mn

C. 99/42Mo. Explanation: The total number of neutrons and protons (atomic mass) for molybdenum-99 is 99. This value goes in the left-hand superscript. The left-hand subscript is the atomic number for molybdenum found on the periodic table, 42. Finally, the element symbol for molybdenum is Mo.

Which of the following gives all of the information necessary to determine the number of subatomic particles? Select the correct answer below: A. mass number B. atomic number C. atomic symbol D. element name

C. Atomic symbol. Explanation: The atomic symbol includes the elemental symbol, the atomic number and the mass number. The latter two are the number of protons and the sum of the number of protons and neutrons, so it is possible to find the number of neutrons by subtracting atomic number from mass number.

What is the chemical formula for calcium bromide? Select the correct answer below: A. Ca2Br B. BrCa C. CaBr2 D. CaBr3

C. CaBr2. Explanation: Calcium forms Ca2+ cations, and bromide refers to a Br− anion. In order for the charges to cancel, we need 2Br− anions for every one Ca2+ cation.

In what temperature scale does water boil at 100∘? Select the correct answer below: A. Fahrenheit B. Kelvin C. Celsius D. Grams

C. Celsius. Explanation: Water boils at 100 degrees in Celsius, 373.15 degrees in Kelvin and 212 degrees in Fahrenheit. The gram is a unit of mass, not temperature.

Which of the following is NOT a field of study that would require chemistry. A. Genetics B. Technology C. Education D. Medicine

C. Education. Explanation: Chemistry aids in the understanding of STEM disciplines. Genetics, technology, and medicine would all require chemistry. The E in STEM stands for engineering, not education.

In general, covalent bonding can occur between which of the following? Select the correct answer below: A. An ion and a neutral atom B. Two ions of opposite charge C. Two neutral atoms D. Any combination above

C. Two neutral atoms. Explanation: Covalent bonding occurs between two neutral atoms; the electrons are shared between the two atoms so that each can fill its octet. Ions are not typically involved in covalent bonding.

Chicken noodle soup is an example of Select the correct answer below: A. a homogenous mixture. B. a pure substances. C. a heterogenous mixture. D. a compound.

C. a heterogenous mixture. Explanation: Heterogeneous mixtures are not uniformly mixed on an atomic or molecular level. Chicken noodle soup is not uniformly mixed, as it contains many ingredients that come together to form it (for example: broth, chicken, noodles, carrots, celery, etc.) Since each component is identifiable on its own, chicken noodle soup is considered a heterogenous mixture.

Which group does lithium belong to? Select the correct answer below: A. noble gases B. halogens C. alkali metals D. alkaline earth metals

C. alkali metals

Which of the following does NOT correctly match the ion name with its ion symbol? Select the correct answer below: A. magnesium cation, Mg2+ B. barium cation, Ba2+ C. aluminum cation, Al3− D. iodide, I−

C. aluminum cation, Al3−. Explanation: All of the answer choices are correctly paired except for the aluminum cation, whose symbol should be Al3+.

C. atomic symbol. Explanation: The atomic symbol includes the elemental symbol, the atomic number and the mass number. The latter two are the number of protons and the sum of the number of protons and neutrons, so it is possible to find the number of neutrons by subtracting atomic number from mass number.

What can be observed without changing the composition of matter? Select the correct answer below: A. flammability B. reactivity C. boiling point D. toxicity

C. boiling point. Explanation: A physical property can be observed without changing the composition of matter. Flammability, toxicity, and reactivity are all chemical properties, whereas boiling point is a physical property.

Which element belongs to the alkaline earth metals? Select the correct answer below: A. aluminum B. sodium C. calcium D. chromium

C. calcium

Ca(ClO3)2 is called __________. Select the correct answer below: A. calcium chlorite B. calcium hypochlorite C. calcium chlorate D. calcium perchlorate

C. calcium chlorate. Explanation: Ca2+ will combine with ClO−3, the chlorate ion, in a 1:2 ratio.

Sugar and water, with appropriate heat, can create caramel. In this example, sugar is undergoing a ___________. Select the correct answer below: A. electrical change B. kinetic change C. chemical change D. physical change

C. chemical change.

The charges on the proton and electron are typically measured in: Select the correct answer below: A. volts B. amperes C. coulombs D. daltons

C. coulombs. Explanation: These fundamental particles bear the fundamental unit of charge, which is either positive or negative 1.602×10−19 coulombs.

Which van der Waals force is present in all condensed phases? Select the correct answer below: A. hydrogen bonding B. dipole-dipole bonding C. dispersion force D. all of the above

C. dispersion force. Explanation: The dispersion force is present in all condensed phases because it arises from temporary charge development that spontaneously occurs in all compounds.

Hydrogen bonds are formed between hydrogen and _____. Select the correct answer below: A. nonpolar molecules B. cations C. electronegative atoms D. all of the above

C. electronegative atoms. Explanation: Hydrogen bonds are formed between hydrogen and the three most electronegative atoms (nitrogen, oxygen, and fluorine). The relatively large difference in the partial charges of each atom in N−H, O−H and F−H bonds allow for very strong dipole-dipole attractions between molecules that contain them.

Intermolecular forces are all some kind of____. Select the correct answer below: A. gravitational attraction B. nuclear repulsion C. electrostatic attraction D. Kinetic energy

C. electrostatic attraction. Explanation: Intermolecular forces are the various forces of attraction that may exist between the atoms and molecules of a substance due to electrostatic phenomena. This involves involves an electron excess interacting with an electron deficiency. The attraction caused by IMFs serve to hold particles close together, whereas the particles' kinetic energy provides the energy required to overcome the attractive forces and thus increase the distance between particles.

Each square on the periodic table represents a(n): Select the correct answer below: A. period B. group C. element D. family

C. element. Explanation: Each square on the periodic table represents a singular element. The symbol is a short letter combination that is used as a standard across many languages. The symbol is often derived from the common or Latin name of the element.

When water becomes ice, it undergoes a physical change based on its: Select the correct answer below: A. reactivity B. basicity C. freezing point D. flammability

C. freezing point. Explanation: The process of transforming liquid water into ice refers to freezing. The freezing point of a substance is a physical property.

Which phase exhibits the weakest intermolecular forces? Select the correct answer below: A. solids B. liquids C. gases D. these will all exhibit the same degree of interaction

C. gases. Explanation: The gas phase is the only phase where we consider the particles to be essentially not interacting with one another at all, as the particles are far apart rather than being in constant contact.

The vertical columns of the periodic table are known as: Select the correct answer below: A. rows B. columns C. groups D. periods

C. groups. Explanation: Groups are labeled at the top of each column. In the United States, the labels were traditionally Roman numerals with capital letters. All columns, apart from the transition metals, are numbered from IA to VIIA. The transition metals (in the middle of the periodic table) are numbered from IB to VIIIB. However, IUPAC recommends that the numbers 1 through 18 be used, and these labels are more common.

Dipole-dipole attractions increase in magnitude with __. Select the correct answer below: A. increasing molecular mass B. decreasing molecular mass C. increasing bond polarity D. none of the above

C. increasing bond polarity. Explanation: As covalent bonds become more polar, dipoles become greater in magnitude, and thus the resulting dipole-dipole attractions increase in magnitude.

Copper ions act as the cofactor in cellular energy production. Identify some sources of copper from the list below. Select the correct answer below: A. milk, kale, and cheese B. red meat and seafood C. liver, sunflower seeds, and lentils D. none of the above

C. liver, sunflower seeds, and lentils. Explanation: Red meat and seafood are sources of iron ions. They are not major sources of copper ions. Iron ions bind oxygen in hemoglobin.

For a given atom, which of the following is typically the largest in value? Select the correct answer below: A. atomic number B. number of protons C. mass number D. all of the above are typically equal

C. mass number. Explanation: The mass number is equal to the number of protons and neutrons in the nucleus. This is typically larger than the atomic number, which is equal to the number of protons. The only exception would be hydrogen, which will typically have an atomic number and mass number both equal to one.

Atoms of the same element can have different: Select the correct answer below: A. atomic numbers B. numbers of protons C. mass numbers D. none of the above

C. mass numbers. Explanation: By definition, atoms of a given element have a particular atomic number (which is the same as the number of protons), but they can have different mass numbers if they have differing numbers of neutrons.

C12H22O11 is an example of a(n): Select the correct answer below: A. ionic compound B. empirical compound C. molecular compound D. salt compound

C. molecular compound. Explanation: it consists of two or more elements that are nonmetals, and are covalently bonded.

The mass number is essentially the sum of the number of ________ in an atom. Select the correct answer below: A,. protons and electrons B. neutrons and electrons C. protons and neutrons D. protons and neutrons and electrons

C. protons and neutrons. Explanation: As the protons and neutrons are each approximately one atomic mass unit, the mass number will simply be the sum of the numbers of these particles. Electrons are negligible in mass.

SiO2 is called __________. Select the correct answer below: A. silicon oxide. B. silicon monoxide. C. silicon dioxide. D. silicon trioxide.

C. silicon dioxide. Explanation: Two oxygen atoms will require the prefix "di." Since oxygen is the second element, you have to add the suffix "ide."

Which of the following is NOT a chemical change? Select the correct answer below: A. sodium metal and chlorine gas form sodium chloride B. an iron pipe rusts C. tap water is run through a filter D. milk turns sour

C. tap water is run through a filter. Explanation: Filtration will separate substances, but no chemistry is occurring, so it is not an example of a chemical change. Formation of sodium chloride, a rusting pipe, and milk turning sour are all examples of chemical changes.

Which of the following is NOT a physical property of a bronze coin? Select the correct answer below: A. that it is shiny B. that it is hard and durable C. that it will slowly change color over many years D. that it sinks in water

C. that it will slowly change color over many years. Explanation: The slow color change is due to chemistry that the material participates in over time, and is therefore not a physical property like the other options.

Which of the following is used to abbreviate an element or an atom of a given element? Select the correct answer below: A. the mass number B. the atomic mass C. the chemical symbol D. the atomic number

C. the chemical symbol. Explanation: An element is is a substance that cannot be broken down or changed. Each element is represented with a chemical symbol which is an abbreviation for the element or an atom of an element.

What is the standard SI unit of mass? Select the correct answer below: A. the pound B. the meter C. the kilogram D. the gram

C. the kilogram. Explanation: The standard SI unit of mass is the kilogram. The gram and the pound are also units of mass but only the kilogram is the SI unit of mass. The meter is the SI unit of length.

For a number written in scientific notation, 1.02×10−7, what does the exponent represent? Select the correct answer below: A. the amount of zeros to add to the digit term B. how many times to multiply the digit term by itself C. the power of ten the digit term is multiplied by D. reliability of the digit term to the accepted value.

C. the power of ten the digit term is multiplied by. Explanation: In scientific notation, the digit term (also known as the mantissa) is the number before the times symbol, and it gives the precise value of the number. The exponent (b) gives the order of magnitude of the number (power of 10) and can be used to count the number of decimal shifts from the mantissa to write the number in standard notation.

If a hypothesis is shown to be accurate after multiple tests, then: Select the correct answer below: A. it becomes a law B. it will never be proven incorrect C. there is still a chance that it could be proven wrong D. it can be applied to multiple observations

C. there is still a chance that it could be proven wrong. Explanation: Even if a hypothesis is shown to be accurate after multiple tests, there is still a chance that it could be proven wrong.

Dispersion forces are specifically the interaction between_____. Select the correct answer below: A. two formal dipoles B. an instantaneous dipole and a permanent dipole C. two temporary dipoles D. none of the above

C. two temporary dipoles. Explanation: It is these temporary dipoles, whether instantaneous or induced, that comprise the dispersion forces.

The modern periodic table is based on one proposed by: Select the correct answer below: A. Antoine Lavoisier B. Lothar Meyer C. John Dalton D. Dmitri Mendeleev

D. Dmitri Mendeleev. Explanation: While other formats had been proposed, it was the predictive powers of Mendeleev's table that caused it to be the basis of chemistry from then on.

Which of the following elements will form a molecular compound with one another? Select the correct answer below: A. F and Na (sodium) B. F and Ca (Calcium) C. F and Mg (Magnesium) D. F and O (oxygen)

D. F and O. Explanation: Oxygen is the only other nonmetal listed, so it is the only combination that could yield a molecular compound.

Which group on the periodic table contains the halogens? Select the correct answer below: A. 1 B. 2 C. 16 D. 17

D. 17

What is 0.29 km in mm? Select the correct answer below: A. 2.9 mm B. 290 mm C. 29,000 mm D. 290,000 mm

D. 290,000 mm. Explanation: There are 1000 meters in 1 kilometer and 1000 millimeters in 1 meter, so there are 1,000,000 millimeters in a kilometer.

Which measurement of the length of an object is the most precise? Select the correct answer below: A. 4.3 cm B. 4.30 cm C. 4.308 cm D. 4.3084 cm

D. 4.3084 cm. Explanation: The more significant figures there are in a value, the more precise of a measurement it represents.

How many periods are present on the periodic table? Select the correct answer below: A. 4 B. 5 C. 6 D. 7

D. 7. Explanation: The periodic table arranges the elements in increasing order of their atomic numbers and groups atoms with similar properties in the same vertical column. All of the elements on the table fit into 7 periods.

What is the formula of the ionic compound, aluminum sulfide? Select the correct answer below: A. Al2S B. AlS C. Al3S2 D. Al2S3

D. Al2S3. Explanation: Because the ionic compound must be electrically neutral, it must have the same number of positive and negative charges. Two aluminum ions, each with a charge of 3+, would give us six positive charges, and 3 sulfide ions with a charge of 2−, would give us six negative charges. Therefore, the formula is two aluminum ions to three sulfide ions: Al2S3.

The macronutrient(s) present in food are __________. Select the correct answer below: A. proteins B. carbohydrates C. fats or oils D. all the above

D. All of the above. Explanation: The three major macronutrients present in food are proteins, carbohydrates, and fats or oils, constituting considerable amounts of calories in the food item.

Which is NOT a property of the alkaline earth metals? Select the correct answer below: A. React with oxygen in a 1:1 ratio. B. They are shiny. C. Conduct electricity. D. They are gases.

D. They are gases. Explanation: The alkaline earth metals, in group 2 are solid metals.

Why do metals and nonmetals usually form ionic compounds, whereas two bonded nonmetals are never ionic? Select the correct answer below: A. Nonmetals can share and transfer electrons. B. Metals can share and transfer electrons. C. Two metals would share electrons which would make a covalent, not an ionic bond. D. Two nonmetals would share electrons which would make a covalent, not an ionic bond.

D. Two nonmetals would share electrons which would make a covalent, not an ionic bond. Explanation: Metal transfer electrons while nonmetals either share electrons with other nonmetals or "receive" electrons from metals. Therefore, electron sharing between 2 nonmetals would always be covalent, not ionic.

N2O5 is called _____________. Select the correct answer below: A. nitrogen oxide. B. nitrogen pentoxide. C. dinitrogen oxide. D. dinitrogen pentoxide.

D. dinitrogen pentoxide. Explanation: The name of the more metallic element (the one farther to the left and/or bottom of the periodic table) is first, followed by the name of the more nonmetallic element (the one farther to the right and/or top) with its ending changed to the suffix -ide.

What is the name of the molecular compound P2O5? Select the correct answer below: A. phosphorus oxide B. diphosphorus oxide C. phosphorus pentoxide D. diphosphorus pentoxide

D. diphosphorus pentoxide. Explanation: The first symbol, P, represents phosphorus. The subscript, 2, indicates that there are two phosphorus atoms present. Because of this, we use the prefix di-, resulting in the first part of the compound name: diphosphorus. The second element in the formula, O, represents oxygen. We use the root ox- plus the suffix -ide, giving us oxide. However, note the subscript 5, which indicates 5 atoms. This means we must add the prefix for 5, penta-, to the name, resulting in pentoxide. Because there are consecutive vowels present, the "a" from penta- is dropped. The name of this compound is diphosphous pentoxide.

What is produced as a result of rapidly fluctuating induced dipoles and instantaneous dipoles? Select the correct answer below: A. ionic bonding B. hydrogen bonding C. dipole-dipole bonding D. dispersion force

D. dispersion force. Explanation: The electrons of an atom are in constant motion so they can spontaneously develop a dipole if the electrons are distributed asymmetrically. This dipole can distort neighboring electrons and cause induced dipoles. Both these dipoles rapidly fluctuate producing a weak electrostatic attraction known as the dispersion force.

What are arranged on the periodic table? Select the correct answer below: A. molecules B. compounds C. periods D. elements

D. elements. Explanation: The periodic table of the elements contains information about single types of atoms and is useful throughout chemistry.

Which of the following is the correct name for F−? Select the correct answer below: A. fluorion B. fluorine ion C. fluorine D. fluoride

D. fluoride. Explanation: Simple anions are named by replacing the end of the element name with -ide.

A mixture of sand and water would be best described as what type of mixture? Select the correct answer below: A. elemental mixture B. pure substance C. homogeneous mixture D. heterogenous mixture

D. heterogenous mixture. Explanation: A heterogenous mixture is one in which the composition throughout changes, much like sand and water.

Chocolate chip cookies are a __________ mixture. Select the correct answer below: A. pure substance B. homogenous C. heteronormative D. heterogenous

D. heterogenous. Explanation: You can see the various chocolate chips, nuts, and cookie dough in chocolate chip cookies, making them a heterogenous mixture.

The chemical symbol "CL" with two capital letters is used to represent which element? Select the correct answer below: A. chlorigen B. chlorine C. clorominium D. it is not a valid chemical symbol

D. it is not a valid chemical symbol. Explanation: CL is not a valid chemical symbol because chemical symbols that contain 2 letters must have one upper case letter and one lower case letter, not 2 upper case letters.

MgCl2 is called __________. Select the correct answer below: A. magnesium dichloride B. magnesium chlorate C. monomagnesium chlorate D. magnesium chloride

D. magnesium chloride. Explanation: We do not need a prefix for magnesium, and chlorine will become chloride, giving us magnesium chloride.

The group that is least likely to ionize is the __________. Select the correct answer below: A. alkali metals B. transition metals C. halogens D. noble gases

D. noble gases. Explanation: The noble gases are also called the inert gases because they are very unlikely to react. This is because they have a full valence shell of electrons, which means they do not want to gain or lose any electrons. The other groups listed all readily ionize.

What is the measure of how easy it is for another electrostatic charge to distort a molecule's electron cloud? Select the correct answer below: A. wave-particle duality B. variability C. compressibility D. polarizability

D. polarizability. Explanation: If an electron cloud is easily distorted, then it is high in polarizability. If it is difficult to distort, then it is low in polarizability.

Which of the following is the correct name for KBr? Select the correct answer below: A. krypton bromine B. potassium bromine C. krypton bromide D. potassium bromide

D. potassium bromide. Explanation: KBr is potassium bromide, a binary compound with monatomic ions.

Molecular compounds differ from ionic compounds because atoms will __________ electrons in molecular compounds instead of gaining or losing them. Select the correct answer below: A. destroy B. migrate C. accumulate D. share

D. share.

Today, the meter is based on: Select the correct answer below: A. a meter stick B. the height of a king C. a fraction of the distance from the equator to the north pole D. the distance light travels in a particular fraction of a second

D. the distance light travels in a particular fraction of a second. Explanation: The meter was once defined as a particular fraction of the distance from the equator to the north pole, but it was eventually revised to be more universal.

Enter the formula for magnesium nitride.

Mg3N2. Explanation: Step 1: Identify the symbol of the first element and its charge. Result of this step: Mg2+. Step 2: Identify the symbol of the second element and its charge. Result of this step: N3−. Step 3: Use the minimum number of cations and anions needed to make the sum of all charges in the formula equal to 0. Result of this step: Mg has a 2+ charge, and N has a 3− charge. To balance these charges, we need three equivalents of Mg2+ and two equivalents of N−. Thus, three Mg2+ ions and two N3− ions are required. The resulting formula of this compound is Mg3N2.

Name a positive ion that is an important component of bone in the human body. Give the chemical formula with the charge.

Mg^2+ or Ca^2+. Explanation: Both magnesium and calcium ions are important positive ions in the structure of bone. They both have a charge of +2 because they are in Group 2 of the periodic table. The carbonate and phosphate ions are also important in bone structure, but they are negative ions.

Ammonium hydroxide has the formula __________.

NH4OH. Explanation: Step 1: Identify the symbol of the cation: Result of this step = NH+4. Step 2: Identify the formula of the anion: Result of this step = OH−. Step 3: Use the minimum number of cations and anions needed to make the sum of all charges in the formula equal to zero: Result of this step = Ammonium has a 1+ charge and hydroxide has a 1− charge, which equate to zero. Putting these ions together gives the formula NH4OH, which is named ammonium hydroxide.

Which two positive ions are important for nerve transmission and fluid regulation? Give the chemical formulas. Be sure to include the charge.

Na^+ and K^+. Explanation: Sodium and potassium ions are important for fluid regulation and nerve transmission. They both have a charge of +1 because they are both in Group 1 of the periodic table. Chloride ions are also important, but have a negative charge.

Sulfur hexafluoride has the formula ______________.

SF^6. Explanation: The name indicates 1 sulfur atom and the prefix "hexa-" indicates 6 fluorine atoms.

What element has an atomic number of 50? Report your answer as an element symbol.

Sn (tin). Explanation: Tin has an atomic number of 50 and an atomic mass of approximately 119 amu.

Identify the chemical symbol for the element tin.

Sn. This can be found in group 14 on the periodic table.

What is the chemical symbol for tellurium on the periodic table?

A particular kind of Spanish orange is completely fat free. If one of the oranges has 40 Calories total and a test shows that it contains 1gram of protein, how many grams of carbohydrates does it have? Report your answer with one significant figure.

Use the given Caloric content and the average values of 4Calories per gram for carbohydrates and 4Calories per gram for protein to set up an equation with x as the unknown amount of carbohydrates. 1g protein×4Calories/g protein+xg carb×4Calories/g carb=40Calories. Simplify and solve for x --->4+4x=40, so x=9. There are 9grams of carbohydrates in the orange.

Which of the following molecules will NOT participate in dipole-dipole interactions? Select the correct answer below: a. HBr b. CCl4 c. HCl d. NH3

b. CCl4. Explanation: Only molecules with an overall net dipole will be able to participate in dipole-dipole interactions. Therefore, of the choices given only CCl4 is a nonpolar molecule with no net dipole. Even though it does have polar bonds, the dipoles point in opposite directions and cancel each other out making it a nonpolar molecule that exhibits only London dispersion forces.

Which of the following would have the higher boiling point? Select the correct answer below: a. CO2 b. CH3Cl C. they have the same boiling point D. there is not enough information to determine this

b. CH3Cl. Explanation: Compounds with stronger intermolecular forces will have higher boiling points (ion ion > hydrogen bonding > dipole dipole > london dispersion). CO2 is nonpolar and only has dispersion forces. CH3Cl is polar and has dipole-dipole attractions so it will have the higher boiling point.

Which of the following does NOT exhibit hydrogen bonding? Select the correct answer below: a. H2O b. HBr c. HF d. H3N

b. HBr. Explanation: Hydrogen bonding is an intermolecular force that occurs in polar molecules where a hydrogen atom is directly bonded to a small, highly electronegative atom (nitrogen, oxygen, fluorine). Hydrogen bonding does not occur between H and Br.

Which of the following will NOT exhibit hydrogen bonding to the N atom? Select the correct answer below: a. NH3 b. (CH3)2NH c. NH+4 d. CH3NH2

c. NH+4. Explanation: The ammonium ion (NH+4) does not have any lone pairs available on the nitrogen to form hydrogen bonds. NH3, (CH3)2NH, and CH3NH2 all have lone pairs available on the nitrogen to form hydrogen bonds.

Which of the following groups can exhibit hydrogen bonding? Select the correct answer below: a. F-H b. O-H c. N-H d. all of the above

d. all of the above. Explanation: Molecules with F-H, O-H, or N-H have partial charges that allow for a very strong dipole-dipole attraction to develop known as hydrogen bonding.

Which statement BEST explains why temperature is an intensive property? Select the correct answer below: A. It is a property that is independent of the amount of matter in a sample. B. It is a property that depends on the amount of matter in a sample. C. It is a property that is only viewable when a substance is undergoing a chemical reaction. D. It is a property that is dependent on the chemical properties of the matter.

A. It is a property that is independent of the amount of matter in a sample. Explanation: Temperature is an intensive property because it is independent of the amount of matter for a given sample.

Which group of ions participates in the transmission of nerve impulses? Select the correct answer below: A. Na+,K+,Cl− B. Na+,Mg2+,Cl− C. Mg2+,Ca2+,Cl− D. H+,Mg2+,Fe2+

A. Na+,K+,Cl−. The chloride ion Cl−, sodium ion Na+, and potassium ion K+.

What is the role of potassium ions K+? Select the correct answer below: A. Potassium ions transmit nerve impulses and help maintain fluid balance throughout the body. B. Potassium ions make up a large amount of ionic structure of bone and teeth. C. Potassium ions form a part of binding complex in the hemoglobin on red blood cells. D. Potassium ions are used to form a gradient for energy production.

A. Potassium ions transmit nerve impulses and help maintain fluid balance throughout the body.

Predict the likely ion formation and charge of rubidium. Select the correct answer below: A. Rb+ B. Rb2+ C. Rb− D. Rb2−

A. Rb+. Explanation: Rubidium is in group 1. Main-group elements on the far left of the periodic table tend to form cations with a charge equal to the group number. Therefore, rubidium will lose an electron to gain a noble gas configuration and become Rb+.

A compound has a melting point of 545 degrees Celsius and dissolves well in water. Why? Select the correct answer below: A. The high melting point points toward an ionic compound, though the fact that it dissolves is irrelevant. B. The high melting point points toward a covalent compound, though the fact that it dissolves is irrelevant. C. The high melting point points toward an ionic compound, and the fact that it dissolves is supports that. D. The high melting point points toward a covalent compound, and the fact that it dissolves is supports that.

A. The high melting point points toward an ionic compound, though the fact that it dissolves is irrelevant.

Which is an example of a homogeneous mixture? Select the correct answer below: A. air B. breakfast cereal C. soil D. oxygen

A. air. Explanation: Air is an example of a homogeneous mixture, oxygen is an element and the remaining options are heterogenous mixtures.

NH4NO3 is called ________. Select the correct answer below: A. ammonium nitrate. B. ammonium nitrite. C. nitrogen nitrate. D. nitrogen nitrite.

A. ammonium nitrate. Explanation: NH^+4 is the ammonium ion and NO^−3 is the nitrate ion, hence ammonium nitrate.

What is a cation? Select all that apply: A. an atom that has lost electrons B. an atom that has gained electrons C. an atom with a neutral charge D. an atom with a negative charge

A. an atom that has lost electrons.

Which of these methods is used to measure the caloric content of food? Select the correct answer below: A. bomb calorimetry B. colorimetry C. mass spectrometry D. spectrophotometry

A. bomb calorimetry. Explanation: The average amounts of energy associated with different types of macronutrients are derived from numerous results given by bomb calorimetry of whole foods.

A Lewis symbol that has a non-noble gas element and no electrons represents a ________. Select the correct answer below: A. cation B. anion C. neutral atom D. depends on the element

A. cation. Explanation: Lewis symbols show the valence electrons. If a Lewis symbol has no dots, the atom must have lost its valence electrons, and will therefore be a positively charged cation.

All positively charged ions are called __________. Select the correct answer below: A. cations B. anions C. protons D. electrons

A. cations. Explanation: Cats have paws, making them paws-ative.

Which of the following is NOT a physical property? Select the correct answer below: A. combustibility B. conductivity C. malleability D. elasticity

A. combustibility. Explanation: Combustibility is the measure of how readily something will burn in the presence of oxygen, which is a chemical reaction. Therefore combustibility is a chemical property.

Which of the following is NOT weaker than a hydrogen bond? Select the correct answer below: A. covalent bond B. dipole-dipole attraction C. dispersion force D. none of the above

A. covalent bond. Explanation: Hydrogen bonds are intermolecular forces, not bonds, so they are much weaker than covalent bonds, but much stronger than other dipole-dipole attractions and dispersion forces.

Compounds consisting of atoms that share electrons with one another instead of gaining or losing electrons are called __________. Select all that apply: A. covalent compounds B. ionic compounds C. molecular compounds D. polyatomic compounds

A. covalent compounds and C. molecular compounds. Explanation: When atoms share electrons with one another instead of losing or gaining electrons they form a covalent bond. A covalent bond is when one electron from each atom feels the pull of the other atom's nucleus. The compound that results is called a covalent or molecular compound.

Why is the term "chemical-free" when used to market cleaning products misleading? Select the correct answer below: A. Only synthetically made cleaners are available to purchase. B. Even naturally occurring substances are chemicals. C. "Chemical-free" cleaners would not be effective. D. All cleaners are made in laboratories and contain chemicals.

B. Even naturally occurring substances are chemicals. Explanation: The term "chemical-free" is misleading because all substances are made up of chemicals. Even natural-based cleaners like vinegar or baking soda are chemical compounds. The term is used only to sell products and plays on the misconception that chemicals are toxic.

Which of the following elements will NOT form a covalent bond between one another? Select the correct answer below: A. C and O B. Mg and O C. N and H D. O and H

B. Mg and O. Explanation: Magnesium will very readily ionize, which means it will form an ionic compound with oxygen rather than a covalent one.

Which would you expect there to be more of, types of elements or compounds? Select the correct answer below: A. More elements -- there are more than 100 known elements. B. More compounds -- compounds are made by combining elements, so there are more possible combinations. C. There are the same number of elements and compounds. D. It is impossible to tell, because nobody knows how many compounds there are.

B. More compounds -- compounds are made by combining elements, so there are more possible combinations. Explanation: There are only a little over a hundred elements, but these come together to form an unlimited number of possible compounds. It is true that nobody even knows how many compounds are present on the Earth, but that is partly because there are so many.

The temperature scale we use most frequently in chemistry is: Select the correct answer below: A. Fahrenheit B. Celsius C. Kelvin D. none of the above

C. Kelvin. Explanation: The Kelvin scale is used most often because it is an absolute temperature scale. Celsius is also used, while Fahrenheit is rarely used in the field of chemistry.

What symbol would be used for a measurement in mega liters? Select the correct answer below: A. mL B. ml C. ML D. Ml

C. ML. Explanation: The abbreviation for the prefix "mega" is "M." The abbreviation for "milli" is "m." Liter is abbreviated with a "L."

Which of the following is a molecular compound? Select the correct answer below: A. TiBr3 B. Cu3P C. N2O4 D. NH4Cl

C. N2O4. Explanation: The other choices are ionic compounds.

Predict the likely ion formation and charge of phosphorous. Select the correct answer below: A. P− B. P2− C. P3− D. P4−

C. P3−. Explanation: Phosphorous is in group 15 which is three groups left of the noble gases. Elements in group 15 will have a tendency to gain three electrons in order to achieve a noble gas configuration giving them a charge of 3−.

Which of the following best describes how the periodic table is organized? Select the correct answer below: A. The periodic table is organized by increasing number of electrons. B. The periodic table is organized by increasing atomic weights and similar properties. C. The periodic table is organized by increasing atomic number and similar properties. D. The periodic table is organized in alphabetical order.

C. The periodic table is organized by increasing atomic number and similar properties. Explanation: The periodic table arranges the elements in increasing order of their atomic numbers and groups atoms with similar properties in the same vertical column. The rows represent collections of elements that have the same valence shell. This means the outermost electrons in all the elements in a given period all have roughly the same energy.

Which of the following is a correct statement about different elements that are in the same group in the periodic table? Select the correct answer below: A. They have the same atomic number. B. They have different chemical properties. C. They are in the same column of the periodic table. D. They are in the same row of the periodic table.

C. They are in the same column of the periodic table. Explanation: The vertical columns in the periodic table are called groups. Elements in the same column or group of the periodic table often have similar chemical properties.

CaF2 is called __________. Select the correct answer below: A. calcium difluoride B. calcium fluorine C. calcium fluorite D. calcium fluoride

D. calcium fluoride.

What is the correct name of the following polyatomic ion: CaSO4? Select the correct answer below: A. calcium sulfide B. calcium sulfur C. calcium ion sulfide D. calcium sulfate

D. calcium sulfate. Explanation: Step 1: Identify the cation: Result of this step = Ca^2+ is calcium. Step 2: Identify the anion: Result of this step = SO2^−4 is sulfate. The resulting name of this compound is calcium sulfate.

In the Kelvin scale, 0 K is: Select the correct answer below: A. the temperature at which water freezes B. the temperature at which water boils C. the temperature at which mercury melts D. absolute zero

D. absolute zero. Explanation: 0 K is absolute zero, the lowest temperature possible.

Which group does magnesium belong to? Select the correct answer below: A. noble gases B. halogens C. alkali metals D. alkaline earth metals

D. alkaline earth metals

The prefixes kilo, mega, and giga can be applied to: Select the correct answer below: A. meters B. seconds C. grams D. all of the above

D. all of the above. Explanation: All the prefixes that can be applied to one unit can be applied to any other unit. This is why the metric system is such a powerful way of communicating scientific data.

Which is a sign that a chemical change occurred? Select the correct answer below: A. an increase or decrease in temperature due to the mixing of two substances B. a new color during a reaction C. gas bubbles D. all of the above

D. all of the above. Explanation: An increase or decrease in temperature, a new color, and gas bubbles are all signs that a chemical change has occurred.

Chemical properties include the way a compound reacts with: Select the correct answer below: A. acids B. bases C. atmosphere D. all of the above

D. all of the above. Explanation: Any description of a compound's capacity to do a certain kind of chemistry would be characterized as a chemical property.

The symbol Fe could refer to which of the following? Select the best answer below. A. an iron atom B. The element known as "iron." C. a macroscopic sample of iron D. all of the above

D. all of the above. Explanation: Fe means "iron" and it can be used to represent an individual iron atom in a molecular formula, or a ratio of iron atoms to other elements or compounds in a reaction, or just to represent the element itself without reference to any specific sample of iron.

Which of the following is a characteristic of molecular compounds? Select the correct answer below: A. They have low melting points. B. They have low boiling points. C. Many are gases. D. all of the above

D. all of the above. Explanation: Molecular compounds are typically low-melting solids (like the common phosphorus tetramer, P4), low-boiling liquids (like molecular bromine, Br2), or gases (like carbon dioxide, CO2).

Hydrogen bonding results in______. Select the correct answer below: A. higher boiling points B. higher melting points C. higher heats of vaporization D. all of the above

D. all of the above. Explanation: These are all due to the strong intermolecular forces present in such a substance, making the molecules harder to separate.

Which has the smallest mass? Select the correct answer below: A. an atom B. a proton C. a neutron D. an electron

D. an electron. Explanation: Electrons have much less mass than protons and neutrons, and all of these are much smaller than an atom.

Which physical form of matter has definite shape and volume? Select the correct answer below: A. solid B. liquid C. gas D. none of the above

A. Solid. Explanation: Solids have definite volume and definite shape. Liquids have a definite volume but no definite shape, and gases have no definite volume or shape.

What is the volume of a 5.30g piece of aluminum? The density for aluminum is 2.70gmL.

1.96 mL. Explanation: Rearrange the density equation to solve for volume: d =m/v v =m/d. v =5.30 g/2.70g/mL v =1.96mL.

A cube with a mass of 250.0 g has sides measuring 5.00 cm each. What is the density of this cube in grams per cubic centimeter?

2.00 grams per cubic cm (g/cm^3). Explanation: Density is a mass to volume ratio: density=massvolume. First, calculate the volume of the cube. volume=(5.00 cm)^3=125 cm^3 Next, substitute in the mass and volume and simplify. density=250.0 g/125 cm^3=2.00g/cm^3

If 1 inch.=2.54cm, calculate the number of inches in 75.0cm.

29.4 inches. Explanation: 75.0/2.54=29.4.

When is chemistry encountered in everyday life? Select the correct answer below: A. Washing hair with shampoo. B. A cat jumping to catch a bird. C. Listening to music on the radio. D. Running down the street to catch the bus.

A. Washing hair with shampoo. Explanation: Chemistry is at play when shampoo is used to clean our hair. It is due to the properties of soap (shampoo), water, and oils in dirt that allow soap to clean our bodies.

Which of the following is true? Select the correct answer below: A. a law is formed when testing yields constant observations. B. a law is formed when additional testing supports the hypothesis. C. a theory is formed when testing yields one observation. D. a theory is formed when testing yields multiple observations.

A. a law is formed when testing yields constant observations. Explanation: A law is formed when testing yields constant observations.

Which of the following can only consist of only one kind of atom? Select the correct answer below: A. an element B. a pure substance C. a compound D. a mixture

A. an element. Explanation: Elements consist of only one kind of atom. Compounds and mixtures consist of more than one type of atom. A pure substance is either an element or a compound, so it could consist of one type of atom, but it does not have to.

The prefix pico (p) means: Select the correct answer below: A. 10^6 B. 10^−12 C. 10^−3 D. 10^3

B. 10^−12. Explanation: A picometer is one trillionth of a meter, because pico means 10−12. The prefix for 106 is mega (M), the prefix for 10−3 is milli (m), and the prefix for 103 is kilo (k).

Which statement accurately explains why chemistry is known as "the central science." Select the correct answer below: A. Chemistry is the most important science. B. Basic chemistry knowledge is important for all other sciences. C. Chemistry is the only science that can explain natural phenomena. D. Chemistry is the only science that uses experimentation to test hypotheses.

B. Basic chemistry knowledge is important for all other sciences. Explanation: Because it is so ingrained in other scientific fields, chemistry is often known as the central science.

What is significant about the temperature of 0K? Select the correct answer below: A. It is the temperature at which matter has no density. B. It is the temperature at which atoms stop moving. C. It is the temperature at which atoms cease to exist. D. It is the temperature at which water molecules freeze.

B. It is the temperature at which atoms stop moving. Explanation: A temperature of 0K is absolute zero and is the point at which motion of atoms stop.

Which of the following is an example of applying a knowledge of chemistry to solve a problem? Select the correct answer below: A. Mining coal for energy use. B. Using soap to clean up an oil spill. C. Developing pest resistant crops. D. Building a bridge to connect two cities.

B. Using soap to clean up an oil spill. Explanation: Soap molecules make us of the polarity of the molecules within the soap. One end of the molecule is attracted to the dirts and oils while the other is attracts to the water molecules. This allows the soap to act as an emulsifier and wash away oils and dirts that water is unable to remove on its own.

Which is an example of a compound? Select the correct answer below: A. hydrogen B. water C. mercury D. oxygen

B. Water. Explanation: Water is an example of a compound, as it is comprised of both hydrogen and oxygen. Hydrogen, mercury, and oxygen are all examples of elements.

Explain when trailing zeros should be considered significant. Select the correct answer below: A. When the number has no decimal point. B. When the number includes a decimal point. C. Trailing zeros are always significant. D. Trailing zeros are never significant.

B. When the number includes a decimal point. Explanation: If the number has a decimal point, then all trailing zeros are significant. For example 3200., 320.0 and 0.03200 are all numbers that have two non-zero digits and two significant trailing zeros, for a total of four significant digits. If there is no decimal point, as in 3200, then the trailing zeros are considered either ambiguous or not significant (opinions vary), but never considered to be significant.

Which of the following substances will float when placed in pure water, which has a density of 1.00 g/mL? Select the correct answer below: A. aluminum with a density of 2.70 g/mL B. ethanol with a density of 0.81 g/mL C. milk with a density of 1.03 g/mL D. steel with a density of 7.80 g/mL

B. ethanol with a density of 0.81 g/mL. Explanation: Anything that has a density less than that of pure water will float on the surface of water. Ethanol is the only listed substance with the a density less than 1.00 g/mL.

Temperature is a measure of _______________. Select the correct answer below: A. light energy B. heat energy C. degrees D. warmth

B. heat energy. Explanation: Temperature is a measure of heat energy. Degrees (Celsius, Fahrenheit) are the units we use to measure temperature. Temperature is not a measure of light energy, and warmth is not the best answer.

Characterize the following statement: If you drink coffee before going to bed, it will take longer to fall asleep. Select the correct answer below: A. observation B. hypothesis C. theory D. law

B. hypothesis. Explanation: This can best be described as a hypothesis because it is an idea or prediction about the way things are that must be tested by experiment. If by excessive experiment a relationship is proven, a hypothesis can then become a theory or law.

Which of the following is classified as an element? Select the correct answer below: A. methane B. iron C. ammonia D. steel

B. iron. Explanation: Iron can be found on the periodic table. Methane and ammonia are compounds, and steel is an alloy.

If ice floats on liquid water, then the density of ice is: Select the correct answer below: A. greater than that of liquid water B. less than that of liquid water C. the same as liquid water D. can't be determined

B. less than that of liquid water. Explanation: In order for ice to float, its density must be less than that of liquid water, so that it displaces more water than an amount equivalent to the mass of the ice.

Why is chemistry helpful in understanding how a toaster creates the brown color and crispy texture of toast? Select the correct answer below: A. The properties of the bread molecules are changing in the toaster. B. The toaster uses electricity. C. The composition and/or properties of the surface of the toast are somehow changed by the toaster. D. The process takes place in the atmosphere.

C. The composition and/or properties of the surface of the toast are somehow changed by the toaster. Explanation: Chemistry is the study of the composition, properties, and interaction of matter. The properties of the bread are changed by the toaster, so chemistry should be able to help determine why.

What is the equivalent temperature on the Celsius scale for 0 K? Select the correct answer below: A. 0∘C B. −100.15∘C C. −273.15∘C D. −459.67∘C

C. −273.15∘C. Explanation: The magnitude on Kelvin scale and the Celsius scales is equal. This means that at 0K the Celsius scale would be at −273.15∘C.

How many significant figures are in the number 806?

3. Explanation: All three of the digits shown in 806 are significant figures. Non-zero digits are always significant, as are any 0's that are between non-zero digits.

The number 0.0801 has how many significant figures?

3. Explanation: Non-zeros are significant, as well as zeros in between non-zeros, but leading zeros are not significant.

Which of the following units can be used for time? Select the correct answer below: A. hours B. years C. days D. all of the above

D. all of the above. Explanation: Hours, years, and days can all be used to report measurements of time.

A power plant delivers about 21,000,000,000,000watts of electricity. Write this quantity in terawatts.

21 terawatts. Explanation: The prefix "tera" means 10^12, so 1TW=10^12W. To convert watts to terawatts, move the decimal point to the right 12 times, filling in or removing zeros as needed, and then use a prefix symbol, T, to represent 10^12. 21,000,000,000,000 W=21×1012W=21 TW

What is 198 g + 334.6 g, rounded to the proper number of significant figures?

533 grams. Explanation: The sum of these two numbers, 532.6 g, must be rounded to the units place because that is the same number of decimal places as the value with the least number of decimal places in the question (198 g). Thus the 6 is rounded up and the correctly rounded answer is 533 g.

A hybrid car holds 32 gallons of gas in its tank. If it travels from San Diego to Seattle in three tanks of gas, and gas costs $3.29 per gallon, about how much did the trip cost? Select the correct answer below: A. $316 B. $29 C. $35 D. $380

A. $316. Explanation: 32 gal (3)= 96 gallons. 96 gallons($3.29)=$315.84. Round up to $316.

A tiny gas bubble in a carbonated beverage contains 2.69×1012 carbon dioxide molecules. Write the number of molecules in standard notation. Select the correct answer below: A. 2,690,000,000,000 B. 0.00000000000269 C. 269,000,000,000,000 D. 269,000,000,000

A. 2,690,000,000,000. Explanation: The exponent, 12, is positive, so move the decimal point to the right 12 times, adding 0s as needed to find the value. Therefore, 2.69×1012=2,690,000,000,000.

What is the density of 30 mL of an unknown liquid with a mass of 90 g? Select the correct answer below: A. 3 g/mL B. 0.3 g/mL C. 90 g/mL D. 60 g/mL

A. 3 g/mL. Explanation: Density is derived using the equation D=mass/volume. 90/30=3 grams.

Carbon dioxide has a density of 2.0gL. What mass will a 3.5 L sample of carbon dioxide have? A. 7.0 g B. 0.57 g C. 1.8 g D. 1.1 g

A. 7.0 g. Explanation: If density is mass over volume, then mass is density times volume. m =d×v 7.0g=2.0g/L×3.5 L

Which prefix means one one-hundredth? Select the correct answer below: A. centi B. deci C. milli D. kilo

A. Centi. Explanation: Deci is one tenth, milli is one one-thousandth, and kilo is one thousand.

A compound is a chemical substance composed of two or more kinds of elements in a fixed ratio. By what means can the components of a compound be separated? Select the correct answer below: A. Chemical means B. Physical means C. Chemical or physical means

A. Chemical means. Explanation: A compound cannot be separated into its component elements by physical means, but it can be separated into elements by chemical means.

Which of the following statements about chemistry is accurate? Select the correct answer below: A. Chemical reactions occur in everyday situations. B. Chemical reactions are only observable in a laboratory. C. Only chemists need an understanding of chemical processes. D. Chemistry can only be used to study the properties of atoms.

A. Chemical reactions occur in everyday situations. Explanation: Chemistry is the study of matter and its properties and interactions. Chemical reactions take place in our daily lives and are readily observable outside of the laboratory.

Which of the following statements about the scientific method is true? Select the correct answer below: A. It is a systematic approach to research. B. It begins with performing an experiment. C. A hypothesis is formed at the end of the the process. D. The process provides the basis for the formation of laws.

A. It is a systematic approach to research. Explanation: The scientific method begins with observation and curiosity and provides a systematic approach to experimentation and scientific research.

A pattern that has been established based on verified experimental data that describes an observation but does not provide an explanation as to the reason why said observation occurs is a _________. Select the correct answer below: A. law B. theory C. hypothesis D. none of the above

A. Law. Explanation: A law is a pattern that has been established based on verified experimental data. Laws provide a description of a particular observation, but does not go so far as to explain why the observation occurs. For example, the law of conservation of energy states that energy is neither created nor destroyed but does not explain why this is the case.

The following statement is an example of a ______________. "The force of gravity between two objects is related to the mass of each object and their distance from each other." Select the correct answer below: A. Law B. Theory C. Hypothesis D. Observation

A. Law. Explanation: A law is a statement about an observed phenomenon and is often a mathematical relationship. The statement from the question describes part of the Law of Gravity.

Which of the following careers would require the use of chemistry on a daily basis? Select the correct answer below: A. Pool operator B. Nature conservationist C. Surveyor D. Civil Engineer

A. Pool operator. Explanation: Pool operators need to understand how to check and monitor chemicals within the pool to ensure that the chlorine levels are safe. This is something that they would check daily and requires a knowledge of how chemicals react to each other.

When adding numbers, the sum will have: Select the correct answer below: A. as many decimal places as the number with fewest decimal places. B. as many decimal places as the number with the most decimal places. C. as many significant figures as the number with fewest significant figures D. as many significant figures as the number with the most significant figures

A. as many decimal places as the number with fewest decimal places. Explanation: The rules state that for addition and subtraction we round to the same number of decimal places as the value with the fewest number of decimal places. This is how we adequately propagate the uncertainty of the most uncertain value through the operation.

If object A and object B have the same density, but object A has greater mass, then object A must have: Select the correct answer below: A. greater volume B. smaller volume C. the same volume D. can't be determined

A. greater volume. Explanation: If these objects have the same density, that means they have the same ratio of mass to volume, so a greater mass must also mean a greater volume.

When dealing with significant figures, the rules for adding values are the same as the rules for: Select the correct answer below: A. subtracting values B. multiplying values C. dividing values D. none of the above

A. subtracting values. Explanation: Adding and subtracting follow the same rules when dealing with precision and significant figures.

Length is: Select the correct answer below: A. the measurement of distance B. the amount of matter in an object C. the force per unit area D. the space occupied by any sample of matter

A. the measurement of distance. Explanation: Length is a measurement of distance. Mass is the amount of matter in an object, pressure is the force per unit area, and volume is the space occupied by any sample of matter.

Which of the following substances will take the shape of a container it is placed in? Select the correct answer below: A. water B. ice cubes C. sand D. salt

A. water. Explanation: Water is a liquid, and will take the shape of its container. Ice cubes, sand, and salt are solids. And although they might seem to take the shape of their container when small enough, when separated out, they do not.

How does the scientific method begin? Select the correct answer below: A. with an observation B. by applying common sense to a problem C. asking friends about their opinions D. reading books

A. with an observation. Explanation: The scientific method always begins with an observation, because science aims to explain the natural world.

Place the following steps of the scientific method in the correct order. 1. Hypothesis becomes theory. 2. Curiosity leads to observations. 3. Experiment is performed and results are consistent with prediction. 4. Hypothesis is created. 5. Additional testing is conducted and it supports hypothesis. A. 5, 4, 1, 2, 3 B. 2, 4, 3, 5, 1 C. 3, 5, 2, 1, 4 D. 4, 2, 3, 5, 1

B. 2, 4, 3, 5, 1. Explanation: all scientific investigations start with a simple curiosity based on observations. After that initial step, scientists create a hypothesis and conduct an experiment to test their hypothesis. If much additional testing is done that supports the hypothesis, then it becomes a theory.

If we wish to convert a value in years into days, a conversion factor we could use would be: Select the correct answer below: A. 1 year/365 days B. 365 days/1 year C. 1 year/24 hours D. 24 hours/1 year

B. 365 days/1 year. Explanation: The top and the bottom must be equal to each other, so 365 days and 1 year, as those represent the same length of time. In addition, days must be on top and years on the bottom so that we can appropriately cancel out the existing unit.

Convert 0.006734 into scientific notation. Select the correct answer below: A. 6.734×10 B. 6.734×10−3 C. 6.734×103 D. 6734×10−3

B. 6.734×10−3. Explanation: Scientific notation is used to express very large and very small numbers as a product of two numbers. The first number of the product is usually a number not less than 1 and not greater than 10. The second number of the product, the exponential term, is written as 10 with an exponent. This means that for 0.006734 the first number (coefficient) will be 6.734 and the exponent will be 10−3.

0.738×0.28 is 0.20664 but is rounded to 0.21. Which rule or rules are applied to this calculation? Select all that apply: A. Round the result to the same number of decimal places as the value with the least number of decimal places. B. Round the result to the same number of significant figures as the value with the least number of significant figures. C. Round down if the digit to be dropped is less than 5. D. Round up if the digit to be dropped is 5 or greater.

B. B. Round the result to the same number of significant figures as the value with the least number of significant figures, and D. D. Round up if the digit to be dropped is 5 or greater. Explanation: For multiplication and division, we round the result to the same number of significant figures as the value with the least number of significant figures. In this calculation, this means rounding to two significant figures by dropping all of the digits after and including the 6 in the thousandths place and rounding up to 0.21.

Digestion is a complex biological process which involves several chemical reactions. Which statement below related to digestion is an example of a chemical process in digestion? Select the correct answer below: A. a major part of digestion takes place in the small intestine. B. During the process of digestion, lots of enzymes help to break down food particles into usable nutrients. C. Undigested food leaves the body as feces. D. The first step in digestion is physically breaking food into tiny pieces.

B. During the process of digestion, lots of enzymes help to break down food particles into usable nutrients. Explanation: Thousands of chemical reactions take place during digestion. Enzymes are chemicals that are used to break down food particles into their nutrients to be used by the body. The other statements relate more to the physical process of breaking down food and are better related to anatomy and physiology.

How are organic light emitting diodes (OLEDs), used in many modern displays, related to chemistry? Select the correct answer below: A. Chemistry helped to discover what OLEDs were. B. OLEDs use new materials that were developed using chemistry. C. Chemistry is critical in marketing the new materials. D. The displays are needed to continue to study chemistry.

B. OLEDs use new materials that were developed using chemistry. Explanation: Organic light emitting diodes (OLEDs) are synthesized compounds that are now used in many displays. Chemistry played a role in determining methods for creating these compounds.

Scientific notation is used to express very large and very small numbers using _________. Select the correct answer below: A. the sum of two numbers B. powers of 10 C. rounded values D. decimals

B. Powers of 10. Explanation: Scientific notation, is used to express very large and very small numbers as a product of two numbers. The first number of the product is usually a number not less than 1 and not greater than 10. The second number of the product, the exponential term, is written as 10 with an exponent. The powers of 10 are used to represent numbers that would otherwise be time consuming to write out.

Why is chemistry helpful for understanding why tea smells good? Select the correct answer below: A. The tea leaves are organic, while the water is not. Chemistry is the study of the interaction of organic materials with inorganic materials. B. The smell is a result of the release of compounds from the leaves. The process is described by multiple interactions between the water and the compounds in the leaves, which is an example of chemistry. C. Chemistry is the study of the interaction of matter with air. Since the smell is transported through air, chemistry is involved. D. Chemistry is the study of the interaction of matter with water. Since the leaves are immersed in water, chemistry is involved.

B. The smell is a result of the release of compounds from the leaves. The process is described by multiple interactions between the water and the compounds in the leaves, which is an example of chemistry. Explanation: Chemistry is the study of the properties, composition, and interactions of matter. The release of the smell from the leaves involves multiple interactions between the compounds in the leaves and the water. This is an example of a process that can be described using chemistry.

A substance that has fixed volume, but no fixed shape is a: Select the correct answer below: A. solid B. liquid C. gas D. None of the above

B. liquid. Explanation: A liquid, like water, has a specific volume that can be measured, but it will take on the shape of whatever vessel it is stored in--whether it is a pot, a cup, a bathtub, or a swimming pool.

Density is defined as: Select the correct answer below: A. volume times mass B. mass divided by volume C. volume divided by mass D. mass minus volume

B. mass divided by volume.

Which is NOT a scientific field that is requires a knowledge of chemistry? Select the correct answer below: A. physics B. sociology C. astronomy D. biology

B. sociology. Explanation: Chemistry deals with atoms and subatomic particles, which have properties as dictated by particle physics. Astronomy deals with chemistry in the sense that stars produce all of their chemical elements through nuclear fusion. And biology is intimately linked with chemistry, as the large molecules that make up biological structures obey chemical principles. Sociology deals with factors that are emergent properties of large groups of humans, so there is little to do with chemistry.

What physical state of matter is associated the particles having least amount of thermal energy? Select the correct answer below: A. gas B. solid C. liquid D. All phases of matter contain the same measure of thermal energy.

B. solid. Explanation: Solids have the most rigidly packed particles (molecules, ions, or atoms) because they have the lowest amount of thermal energy compared to the other states of matter for that substance.

Which of the following is a mixture? Select the correct answer below: A. a bar of gold B. sugar water C. helium D. carbon dioxide

B. sugar water. Explanation: Sugar water is comprised of sugar molecules and water molecules, two different substances. The rest are pure substances.

When carrying out operations with significant figures: Select the correct answer below: A. round values as you proceed through the calculation B. wait to round until the end of the calculation C. round sums and differences only D. round products and quotients only

B. wait to round until the end of the calculation. Explanation: To avoid generating rounding errors in calculations involving multiple operations, always wait until the end of the calculation to round your final answer.

While the SI base unit of time is the second, what other unit can also be used? Select the correct answer below: A. Kelvin B. years C. meters D. liters

B. years. Explanation: Although the second is the SI base unit of time, hours, days, and years can all be used as units of time. Kelvin is a unit of temperature, meter is a unit of length, and liter is a unit of volume.

Use dimensional analysis to convert 15.0 inches into centimeters. (1.00 in =2.54 cm). Select the correct answer below: A. 2.54 cm B. 5.09 cm C. 38.1 cm D. 40.3 cm

C. 38.1 cm. Explanation: To convert between inches and centimeters you use the conversion factor: 1.00 in=2.54 cm. 15.0 in×2.54 cm=38.1 cm.

Explain why chemistry is sometimes called "The Central Science". Select the correct answer below: A. Chemistry is typically studied in the central years (tenth and eleventh grade) of a high school education. B. Chemistry is the most important discipline in science. C. Chemistry is highly interconnected with so many other scientific disciplines. D. Other fields of science only connect to each other through chemistry.

C. Chemistry is highly interconnected with so many other scientific disciplines. Explanation: Chemistry is sometimes referred to as â€œthe central scienceâ€ due to its interconnectedness with a vast array of other STEM disciplines (STEM stands for areas of study in the science, technology, engineering, and math fields). Chemistry and the language of chemists play vital roles in biology, medicine, materials science, forensics, environmental science, and many other fields.

Object A has a density of 2.0 g cm3 and a mass of 100 g. Object B a density of 0.8 g cm3 and a mass of 240 g. Object C a density of 5.0 g cm3 and a mass of 100 g. Which of the objects above (A, B, or C) has the smallest volume? A. Object A B. Object B C. Object C D. all of the objects have the same volume

C. Object C. Explanation: volume=mass/density For A: 100 g/2.0 g/cm^3=50 cm^3. For B: 240 g/0.8 g/cm3=300 cm^3. And for C: 100 g/5.0 g/cm^3=20 cm^3. Object C would have the smallest volume.

Why is it important to use a standard system of measurement across all science disciplines? Select the correct answer below: A. Science has unique measurements that need to be taken. B. Conversion factors are easily used between science disciplines. C. So that scientists around the world can easily compare experimental results. D. Science uses the oldest measurements to ensure accuracy.

C. So that scientists around the world can easily compare experimental results. Explanation: Scientists use an international system of measurement and units so that they can easily compare their results and there is consistency.

Jordan measures a cube and finds that each side (length, width, height) of the cube is 3.0cm. She then uses a scale and finds the mass of the block is 243g. What is the density of the block? Of what substance is the block made? A. The density is about 1.0g/cm^3, and the block is oak (wood). B. The density is about 10.0g/cm^3, and the block is silver. C. The density is 9.0g/cm^3, and the block is copper. D. The density is about 9.0g/cm^3, and the block is iron.

C. The density is 9.0g/cm^3, and the block is copper. Explanation: To calculate density you must use the equation density=massvolume. We know each side of the cube is 3.0cm, but that is not our volume. To get our volume, we must multiply the length, width and height of the cube. That means we must use the equation: volume=3.0cm×3.0cm×3.0cm=27 cm3. We can then use our values for volume and mass to calculate density. density=243 g27 cm3=9.0 g/cm^3. We then find this value on our chart and see that it matches the density of copper. Therefore, our cube is made of copper.

Which would NOT be an appropriate unit for density? Select the correct answer below: A. g/mL B. kg/m^3 C. g/s D. all of the above are acceptable

C. g/s. Explanation: Density is an expression of mass per volume, and seconds are a unit of time, so this does not work for density.

Which of the following CANNOT be classified as a compound? Select the correct answer below: A. carbon dioxide B. sodium chloride C. lithium D. sugar

C. lithium. Explanation: Lithium is an element. The rest are made of multiple elements.

What does density measure? Select the correct answer below: A. mass per weight B. weight per mass C. mass per volume D. volume per mass

C. mass per volume. Explanation: Density is the measure of mass per unit volume or how much 'stuff' occupies a certain amount of space.

The oil settles on the surface of the water after an oil spill because: Select the correct answer below: A. it takes a long time to sink B. the water is less dense than the oil C. oil is less dense than water D. the water has more atoms, causing it to sink

C. oil is less dense than water.

When computing using dimensional analysis: Select the correct answer below: A. all unit conversions must be done separately B. all unit conversions must be done in a singular calculation C. unit conversions can be done either simultaneously or separately D. unit conversions are not a part of dimensional analysis

C. unit conversions can be done either simultaneously or separately. Explanation: We can perform unit conversions one at a time or many at a time, just be sure to keep in mind that this could create a discrepancy in the number of significant figures in your result, depending on when you decide to round your value.

What is 498 mm in m? Select the correct answer below: A. 498 m B. 49.8 m C. 4.98 m D. 0.498 m

D. 0.498 m. Explanation: Multiplying the original value by the conversion factor 1 m/1000 mm gives us a value of 0.498 m.

How many kilograms does a 40.0 lb-bag of cat food weigh? (1 lb=454 g). Select the correct answer below: A. 11.4 kg B. 0.088 kg C. 2.40 kg D. 18.2 kg

D. 18.2 kg. Explanation: Begin by starting with the value of 40.0 lb and multiply by a fraction that is equal to one that we are already aware of: 40.0 lb×454 g1 lb. When we multiply this value of 40.0 lb by this fraction, we can see that the units cancel, just like an algebraic variable: 40.0 lb×454 g1 lb. We repeat this process with a different conversion until we end up with the desired unit of kg: 40.0 lb×454 g1 lb×1 kg1000 g=18.16 kg. The answer should have three significant figures, so round to 18.2 kg.

35 gigatons equals __________. Select the correct answer below: A. 3.5×10^−9tons B. 3.5×10^−10tons C. 3.5×10^9tons D. 3.5×10^10tons

D. 3.5×10^10 tons. Explanation: The prefix "giga" means 10^9, so it can be written as the following. 35 gigaton=35×10^9 tons To write the number in scientific notation, the decimal part must be between 1 and 10. Move the decimal point in 35 to the left one place, and, since this makes the number smaller by a power of 10, add 1 to the exponent on 10 to compensate. 35×10^9 tons=3.5×10^10 tons.

The moon is 384,400 km from earth. Select the value that corresponds to this distance expressed in scientific notation. Select the correct answer below: A. 384,400 km B. 3844×100 km C. 384.400×103 km D. 3.844×105 km

D. 3.844×105 km. Explanation: The magnitude of this number is greater than 1, so the exponent will be positive. Move the decimal point to the left until the number has a single digit in the ones place. In this case, the decimal point is moved 5 places to the left.

If D represents density, M represents mass, and V represents volume, which equation below shows the correct relationship between mass, volume, and density? A. V=M×D B. D=M×V C. M=V/D D. D=M/V

D. D=M/V.

What is the SI unit used to measure temperature? Select the correct answer below: A. Joule B. Celcius C. farenheit D. Kelvin

D. Kelvin. Explanation: Kelvin is the SI unit for measuring temperature. Joule is an SI unit, but is used to measure energy.

Which of the following does not describe matter? A. Matter takes up space. B. Matter can exist in different phases. C. Matter has mass due to its atoms. D. Mass is composed of only one type of atom.

D. Mass is composed of only one type of atom. Explanation: Matter is a physical substance that has both mass and volume and can exist in different phases, such as solid, liquid, or gas. It is not a requirement that matter be composed of only one type of atom, though it can be (like a pure element).

What SI unit do we use when measuring distance? Select the correct answer below: A. the yard B. the foot C. the inch D. the meter

D. The meter. Explanation: We use the meter when representing distance in SI units. The yard, foot, and inch measure distance but are not SI units.

Information collected during an experiment is called: Select the correct answer below: A. facts B. knowledge C. opinions D. data

D. data. Explanation: Raw experimental information is called data, which can then be interpreted to form conclusions that lead to knowledge, facts, and opinions.

In dimensional analysis, what is a conversion factor? Select the correct answer below: A. accepted values for physical quantities B. theoretical quantities of matter C. experimental values for given quantities of matter D. ratios of physical quantities used to compare desired units

D. ratios of physical quantities used to compare desired units. Explanation: Conversion units are ratios of physical quantities used to compare between two desired units. They are not experimental or theoretical.

Volume is the: Select the correct answer below: A. basic unit for measuring distance B. amount of matter in an object C. force per unit area D. space occupied by any sample of matter

D. space occupied by any sample of matter. Explanation: Volume is the space that is occupied by any sample of matter. The meter is the SI unit for measuring distance or length, mass refers to the amount of matter in an object, and pressure is the force per unit area.

Homogeneous mixtures may be in any phase EXCEPT: Select the correct answer below: A. gas B. liquid C. solid D. they may be in any phase

D. they may be in any phase. Explanation: Mixtures of gases will always be homogeneous. Mixtures of liquids are often homogeneous, like ocean water. Solids can also be homogeneous mixtures when considering alloys of different metals.

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