CHEM 101

The percentage by mass of a compound by each of its elements is known as its: formula mass mass unit percent composition mole

percent composition The percent composition is the percentage by mass of each element in a compound.

significant figures

(also, significant digits) all of the measured digits in a determination, including the uncertain last digit

What is the atomic mass of xenon? Your answer should have six significant figures.

131.294

Express 100 kmhr in meters per second. Report your answer with three significant figures.

27.8

Complete the following operation to the correct number of significant figures: 85.2÷25.90348= 3.289 3.28 3.29 3.3

3.29

What is the mass of 4.45×1022 tin (Sn) atoms? Use 6.022×1023atomsmole for Avogadro's number. Perfect. Your hard work is paying off 😀 118g 60.2g 44.5g 8.77g

8.77g To calculate the mass of 4.45×1022 tin atoms, use Avogadro's number to calcuate the number of moles, and the molar mass of tin to convert moles to mass in grams. 4.45×1022 atoms×1 mol6.022×1023 atoms×118.711 g1 mol=8.772 g After rounding to three significant figures, we find that 4.45×1022atomsof tin have a mass of approximately 8.77g.

Which field is referred to as the central science? A. physics B. chemistry C. biology D. geology

B. chemistry

All of the following are reasons why chemistry is known as the "central science", EXCEPT: A. Many biological processes involve chemical reactions. B. Because it intersects with and provides a basis for a variety of other scientific disciplines. C. Because it is crucial to understanding other scientific concepts like energy transfer. D. Because it was created to study all other sciences.

Because it was created to study all other sciences.

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?

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

If a compound's chemical formula was experimentally determined to be 18, the chemical formula could be: CH4 NH3 H2O PCl5

H2O Use the periodic table to get the atomic masses of each element. Then you can calculate the formula mass as such: H=1.008×2=2.016 O=15.999×1=15.999 Adding these together we get 18.015, which is approximately 18.

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

It is a systematic approach to research.

If you are asked to report a temperature in base SI units, which scale might you use? Kelvin Celsius Celsius, kelvin, or fahrenheit fahrenheit

Kelvin

In what temperature scale does water freeze at 273.15? Kelvin Fahrenheit Celsius All of the above

Kelvin

What is the SI unit used to measure temperature? A. Joule B. Celcius C. Farenheit D. Kelvin

Kelvin

In which temperature scale is the boiling point of water represented by the largest number?

Kelvin The boiling point of water is 100 Celsius, 212 Fahrenheit, and 373 Kelvin. Therefore the boiling point of water is represented by the largest number on the Kelvin scale.

Which physical form of matter has a definite volume, but no definite shape?

Liquid Liquid is a physical form of matter that has a definite volume, but no definite shape. A solid has a definite volume and definite shape, and a gas has no definite volume or shape.

If a compound has a formula mass of 35, the chemical formula could be: NaOH LiF NH4OH NaF

NH4OH Use the periodic table to get the atomic masses of each element. Then you can calculate the formula mass as such: N=14.007×1=14.007H=1.008×5=5.040O=15.999×1=15.999 Adding these together we get 35.046, which is approximately 35 amu.

Which of the following are valid chemical symbols? Select all that apply. O He F Ua

O He F O (oxygen), He (helium), and F (fluorine) are all valid chemical symbols. Ua is not a valid chemical symbol, as no corresponding element exists.

Of the two classifications for mixtures, which of the following represents a mixture with a uniform composition throughout? binary mixture homogeneous mixture heterogenous mixture pure mixture

Of the choices listed, a homogeneous mixture is one of the two classes of mixtures. The second is a heterogeneous mixture. A homogeneous mixture has a uniform composition of its components throughout.

Which of the following is a correct method for determining the number of neutrons in an atomic nucleus? The mass number is equal to the number of neutrons. Subtract the atomic number from the mass number. Add the atomic number and the mass number. Determine the number of protons; the number of neutrons is always equal to the number of protons in an atomic nucleus.

Subtract the atomic number from the mass number. 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

Which is NOT a property of the alkaline earth metals? React with oxygen in a 1:1 ratio. They are shiny. Conduct electricity. They are gases.

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

Which of the following is NOT a substance made of one type of molecule. carbon dioxide glucose water a cell within the human body

a cell within the human body A cell is a collection of many different types of molecules.

A large change in temperature (not resulting from external heating) with the appearance of gas bubbles is most likely an indication of: a chemical change only physical changes occurring molecules are undergoing physical changes none of the above

a chemical change A large change in temperature with the appearance of gas bubbles indicates that a chemical change has most likely occurred.

Which has the smallest mass? an atom a proton a neutron an electron

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

Atoms that form ions with a positive charge are known as __________. neutrons protons anions cations

cations Atoms that form ions with a positive charge are known as cations.

Which prefix means one one-hundredth? centi deci mili kilo

centi

Which of the following is NOT a physical property? combustibility conductivity malleability elasticit

combustibility 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.

There can be more than one compound with the same: Correct! You nailed it. empirical formula but not molecular formula molecular formula but not empirical formula empirical formula or molecular formula none of the above

empirical formula or molecular formula Compounds with different molecular formulas can have the same empirical formula, and it is also possible for two different compounds, called isomers, to have the same molecular formula.

uncertainty

estimate of amount by which measurement differs from true value

The chemical symbol "CL" with two capital letters is used to represent which element? Keep trying - mistakes can help us grow. chlorigen chlorine clorominium it is not a valid chemical symbol

it is not a valid chemical symbol 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.

The subatomic particle labeled "B" can be correctly identified as either a(n) _______________ or a(n) ________________. Select two that apply. proton neutron electron nucleus

proton neutron Label B is pointing to a subatomic particle that is found inside the nucleus (labeled with an A) on an atom. The two subatomic particles in the nucleus are protons and neutrons so label B could be either one.

Which two particles have roughly the same mass? proton and neutron proton and electron neutron and electron atom and neutron

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

The lanthanides and actinides belong between: the alkaline earth metals and the transition metals the alkali metals and the alkaline earth metals the halogens and the noble gases the metalloids and nonmetals

the alkaline earth metals and the transition metals The lanthanides and actinides belong between group 2 and the transition metal block. They are simply removed and placed below the rest of the table for practicality.

What determines the mass of an object? the volume of the object the weight of the object the density of the object the amount of matter in the object

the amount of matter in the object

Iron melts at 1535∘C. What would this temperature be in Fahrenheit? Your answer should have four significant figures. (Round your answer to the nearest whole number). Do not include units in your answer.

2795 The equation relating Celsius and Fahrenheit is T∘F=(9∘F5∘C×T∘C)+32∘F. T∘F=(9∘F5∘C×1535∘C)+32∘F=2763∘F+32∘F=2795∘F

An LCD TV was put in a box of size 12×24×24 inches. What is the volume of the box in cubic feet?

4 ft

A thermometer reads 25∘C. If the temperature in the room is then increased by 16 K, what temperature will the thermometer read, in degrees Celsius? Round the answer to two significant figures (round to the nearest whole number).

41 degrees Celsius The magnitude of 1K is equal to the magnitude of 1∘C. Therefore, this temperature can be found by adding the temperature change, in Kelvin, to the temperature in Celsius. 25∘C+16K=41∘C Notice that the freezing temperature of water in Kelvin is 273.15K, and its boiling temperature 373.15K. The numerical difference in these two reference temperatures is 100, the same as for the Celsius scale.

Complete the following operation to the correct number of significant figures: 4.5×11.41= 51.345

51

An object has a mass of 0.124kg and a volume of 1893mm3. What is its density in grams per cubic centimeter? Your answer should have three significant figures (round your answer to one decimal place).

65.5 Divide the mass by the volume in order to find the density, and then use conversion factors to cancel the given units and leave the desired units. density=0.124kg1893mm3 To convert from kilograms to grams, use the relationship 1kg=1000g. The conversion factor 1000g1kg cancels kilograms and leaves grams. In the denominator, use the relationship 1cm=10mm. Since these are cubic units, use the conversion factor (10mm1cm)3=1000mm31cm3 to cancel cubic millimeters and leave cubic centimeters. Now calculate the density with the converted units. density=0.124kg1893mm3×1000g1kg×1000mm31cm3=65.505gcm3 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 calculation, the numbers in the unit conversions are exact numbers. The mass of 0.124kg has the fewest number of significant figures, so the answer has three significant figures. Round the answer to 65.5gcm3.

Many sciences are important in understanding how hormones are synthesized in the body. Which science would a doctor be required to have a basic knowledge of in order to understand these chemical processes? A. chemistry B. biology C. ecology D. physiology

A. chemistry

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. Round the result to the same number of decimal places as the value with the least number of decimal places. Round the result to the same number of significant figures as the value with the least number of significant figures. Round down if the digit to be dropped is less than 5. Round up if the digit to be dropped is 5 or greater.

Round the result to the same number of significant figures as the value with the least number of significant figures. Round up if the digit to be dropped is 5 or greater. 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.

A __________ contains more than one type of substance as part of its composition.

mixture

Despite the units frequently seen on laboratory scales, the most appropriate unit below for quantifying weight is _______. kelvin grams amperes newtons

newtons Newtons measure force, and weight is the force exerted by an object because of its position in a gravitational field. Kelvin measures temperature, grams measure mass, and amperes measure electrical current. Most laboratory scales purport to measure mass and display grams (or kilograms or milligrams) rather than newtons, because it is assumed that they will be used on Earth and most chemists would need to convert the weight to a mass anyway.

An atom of an element can be split into smaller components by what kind of process? a physical process a chemical process magnetic force none of the above

none of the above An atom of an element cannot be split into its components by either a physical or chemical change. Splitting an atom is a nuclear process.

exact number

number derived by counting or by definition

Which of the following is NOT a SI base unit? A. m B. s C. oz D. cd

oz

Which of the following is an example of a heterogenous mixture? gasoline air a sports drink salad dressing

salad dressing

Which of the following is measured using Newtons (a unit of force)?

weight

How many SigFigs are present in the value: 100,300 A. 2 B. 3 C. 4 D. 5 E. 6

4

How many electrons does O2− contain?

$10\ \text{ electrons}$10 electrons​ 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

What is the atomic mass of mercury? Your answer should have six significant figures.

$200.592\text{ amu}$200.592 amu​ Mercury has an atomic mass of 200.592 amu and an atomic number of 80

Identify the chemical symbol for krypton. Provide your answer below:

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

Gallium has two stable isotopes: 69Ga and 71Ga with masses of 68.9255736 amu and 70.9247013 amu. If the average atomic mass on Earth is 69.726 amu, then which isotope is more common? Enter the appropriate isotope number.

$\text{gallium-}69$gallium-69​ Since the average mass is closer to the isotopic mass of 69Ga and there are only two isotopes, gallium-69 must be more abundant.

Write the atomic symbol (including the atomic number) for phosphorus-32. 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.

$_{15}^{32}P$3215​P​ Using the periodic table to find phosphorus, the symbol is P and the atomic number is 15, which is also the number of protons. The number 32 in the name of the isotope is the mass number. The atomic symbol is written with the atomic number on the lower left and the mass number on the upper left, so it is 3215P.

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

$_{64}^{160}Gd$16064​Gd​ 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 16064Gd.

What is the correctly reported answer to the problem shown? 0.1/

0.11

What is the precise mass of the proton? Correct! You nailed it. 1.00727 amu Exactly 1 amu 0.00055 amu 1.67×10−24 amu

1.00727 amu The mass of the proton is slightly more than 1 amu, but not quite the mass of the neutron. The atomic mass unit is defined to be roughly the same as one proton or neutron, but precise masses of individual atoms cannot be calculated by summing the individual protons and neutrons. Instead 1 amu is defined to be exactly 112 the mass of a carbon-12 atom, and the masses of individual protons and neutrons are slightly larger than 1 amu. The proton has a mass of 1.00727 amu

If a sample of CO2 contains 48 grams of oxygen, how many moles of CO2are there? Perfect. Your hard work is paying off 😀 0.54 moles 1.4 moles 1.5 moles 2.6 moles

1.5 moles To calculate the number of moles of CO2 in a sample that contains 48 grams oxygen, we need to convert the grams of oxygen into moles of oxygen using our molar mass from the periodic table. 48 grams O×1 mole O15.999 grams O=3.0002 moles O Second, we can see that there are 2 oxygen atoms in the molecule of CO2. This gives us a ratio of 1:2 which we can then use to solve for number of moles of CO2. 3.0002 moles O×1 mole CO22 mole O=1.5

How many electrons does Na+ contain?

10 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: number of electrons=number of protons−overall charge number of electrons=11−(+1)=10

Which of the following has 3 significant figures? Select all that apply. 123 12.3 123000. 1.23 x 10 to the 4th

123, 12.3, 1.23 x 10 to the 4th All of the answer choices have 3 significant figures except for 123000. The decimal point at the end of the number means that the trailing zeros are also significant, so it has 6 total.

Crystal measures the mass of a beaker containing ice cubes and finds that its mass is 130 g. After an hour, the ice cubes have melted, and Crystal decides to take another measurement. What will be the mass of the beaker and the water? 130 g 100 g 65 g There is not enough information to answer this question.

130 g According to the law of conservation of matter, state transformations do not change the mass of a substance. Therefore, the beaker with ice or water will have the same mass.

Two cubes sit side-by-side. The side length of the larger cube is 2.50 times the side length of the smaller cube. How many times larger is the volume of the larger cube than the volume of the smaller cube? Round to three significant figures.

15.6 The side length of the larger cube is 2.5 times that of the smaller. Since the volume of a cube is equal to the side length cubed, the volumes will be related by a factor of (2.5)3. (2.5)3=15.625which, rounded to three significant figures, is15.6. The volume of the larger cube is about 15.6 times the volume of the smaller cube.

How many groups are on the periodic table? 7 10 18 30

18 The 18 groups are represented by the 18 columns on the table. 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 numbers 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

The average high school student spends 330. minutes in class every day. How many seconds is this? Report your answer with the correct number of significant figures.

19,800 secs

If 1 mole of water has a ratio of 1:8 of hydrogen to oxygen by mass, then what will the ratio be for 2 moles of water? Correct! You nailed it. 1:16 2:8 1:8 There is not enough information to answer this question.

1:8 The ratio will always be 1:8 for any size sample according to the law of definite proportions.

The temperature of a substance changes by 1K. This is equal to a temperature change of ________?

1∘C Looking at the image above, we can see that the freezing temperature of water on the Kelvin scale is 273.15 K, and its boiling temperature is 373.15 K. Notice that the numerical difference in these two reference temperatures is 100, the same is true for the Celsius scale. Water freezes at 0∘C and boils at 100∘C which is a difference of 100 in magnitude. This means that 1 K is equivalent to 1∘C in magnitude. This makes the conversion between the Celsius and Kelvin quite easy.

The wavelength of a microwave is approximately 0.02meters. Write this quantity in centimeters.

2

A sample of ethyl alcohol has the following percentages of elements: 35% O, 52% C, and 13% H. If a third of the sample was to evaporate, what will the new percentages be? Perfect. Your hard work is paying off 😀 35% O, 52% C, and 13% H 23% O, 36% C, and 9% H 32% O, 49% C, and 10% H There is not enough information to answer this question.

35% O, 52% C, and 13% H According to the law of definite proportions, the percentage of elements within a molecule will remain the same.

How many moles of sulfur atoms are there in 64 g of S8? Perfect. Your hard work is paying off 😀 2.0 moles 1.3 moles 0.56 moles 0.25 moles

2.0 moles To determine the number of moles, we must first divide the mass, in grams, by the molar mass of the substance. Since we want to know the number of moles of sulfur atoms, we must multiply by 8 sulfur atoms. 64 grams S8×1 mole S8256.528 grams×8 moles S atoms1 mole S8=2.0 moles of S atom

The mass of a sample of CaCO3 is 751 grams. How many total atoms are present in this sample?

2.26×1025 atoms Remember that Avogadro's number tells us only the number of discrete units (in this case, formula units of CaCO3) in a mole. To find the total number of atoms in this sample, we will need to multiply the computed number of formula units by the number of atoms in each unit of this compound (in this case, 5). 751 g×1 mol CaCO3100.1 g×6.022×1023 formula unitsmol=4.52×1024 formula units of CaCO3 Multiplying by the number of atoms in each formula unit gives us: 4.52×1024 formula units of CaCO3×5 atomsformula unit of CaCO3=2.26×1025 atoms

How many atoms are present in a water molecule?

3 There are three atoms present in a water molecule: two hydrogen atoms and one oxygen atom.

One year consists of 365 days. This is closest to how many seconds? (Remember the following conversion factors: kilo (103), mega (106), giga (109), and tera 1012.)

31.5 mega seconds One year is 365 days and each day has 24 hours. 365 days×24 hoursday×60 minuteshours×60 secondsminute=31,536,000 seconds Writing it in scientific notation gives: 31,536,000 seconds=3.1536×107 seconds. Reviewing the values of the prefixes, the exponential factor, 106, can be replaced by "mega," which is the only prefix that has the correct order of magnitude (maximum place value). 3.1536×107 seconds≈31.5 megaseconds

6 grams of salt are dissolved into 35 ml of a solution. After the solution is heated and boiled away, how many grams of salt do you expect to remain? 0 g 3 g 4 g 6 g

6 g The amount of salt will be the same before and after the reaction, so 6 grams of salt will remain.

Which of the following is equivalent to a mole of oxygen atoms? 6.022×1023 oxygen atoms 1.6×1023 oxygen atoms 8 oxygen atoms There is not enough information to answer this question.

6.022×1023 oxygen atoms A mole of oxygen atoms is 6.022×1023 oxygen atoms. In fact, 1 mole of any substance will contain 6.022×1023 atoms because that is the definition of a mole.

Copper occurs naturally as 63Cu and 65Cu. Given that copper's atomic mass is 63.54, determine which isotope is more abundant. 63Cu 65Cu They are equally abundant. There is not enough information to answer this questio

63Cu Because the average atomic mass of copper is closer to 63 than it is to 65, we can conclude that 63Cu is the more abundant isotope.

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: 7 7.01 14.01 14

7 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.

How many moles of hydrogen atoms are there in 120 g of C6H12O6? Well done! You got it right. 8 12 60 120

8 First, we need to find the molar mass of the molecule. We find the molar mass of the molecule using the individual molar masses of the elements and multiplying by the number of atoms of each element. The table below shows how we calculate the molar mass of C6H12O6. ElementMolar Mass Number of Atoms Total H1.008×12=12.096 C12×6=72 O15.99×6=95.94 Total=180.04 Next, you need to convert mass (g) of the molecule into moles. We do this by dividing the molar mass by the mass given in the problem. 120 g C6H12O6×(1 mol180.04 g)=0.67 moles We can then use the number of moles of the substance and the number of atoms from the molecular formula to find the number of moles of an individual element. 0.67 moles×12 H=8 moles H

Heat is usually released or absorbed, but sometimes the conversion involves light, electrical energy, or some other form of energy. Which of the following illustrates this? A car sits in a garage. A windshield on a car is broken. The seat covers in a car are changed. A car drives down a road.

A car drives down a road. When gasoline is combusted within the cylinders of a car's engine, the rapidly expanding gaseous products of this chemical reaction generate mechanical energy (a type of kinetic energy) when they move the cylinders' pistons which is what is occurring when a car is being driven down a road.

Chemistry helps to create: A. New mathematical equations B. New ideas about how humans connect C. New ways to harness renewable energy D. New theories on spiritual connections

C. New ways to harness renewable energy

If a compound's formula mass was experimentally determined to be 58, the chemical formula could be: C2H2 C2H4 C2H6 C3H6

C2H2 Use the periodic table to get the atomic masses of each element. Then you can calculate the formula mass as such: H=1.008×2=2.016 C=12.011×2=24.022 Adding these together we get 26.038, which is approximately 26.

A compound with the empirical formula of CBr2 has a molar mass of 515.46 g/mol. What is the molecular formula of this compound? Well done! You got it right. CBr CBr2 C3Br6 C3Br4

C3Br6 The empirical formula weight is 171.8 g/mol so the molar mass divided by that is 515.46171.8=3. This means the molecular formula is three times the empirical formula, or C3Br6.

The molar mass of a compound if 74.14 g/mol and its empirical formula is C4H10O. What is the molecular formula of this compound? Perfect. Your hard work is paying off 😀 C8H20O3 CHO C2H10O3 C4H10O

C4H10O The empirical formula weight is 74 g/mol so the molar mass divided by that is 74.14/74=1. That means the molecular formula is the same as the empirical formula, or C4H10O.

Citric acid contains 37.51% C, 4.20% H, and 58.29% O by mass. What is the empirical formula of this compound? Great work! That's correct. C6H8O7 CHO C4H6O7 C2H3O

C6H8O7 Assuming 100 g, C=37.51 g, H=4.20 g, and O=58.29 g. The molar quantities for each are: 3.123 C, 4.167 H, and 3.643 O. Dividing by the smallest of these values, we get C=1, H=1.334, and O=1.166, which correspond to 1, 113, and 116. The decimal numbers may not be exactly the correct rounded equivalent, due to rounding errors, but assume the denominators of the fractions will not be too large. For example, 113 is 1.333when rounded to the thousandth, but is close enough to 1.334 to assign to the hydrogen mole ratio. The empirical formula must have whole numbers of each element, so multiply by the common denominator, 6, to get C=6, H=8, O=7.

A compound with the empirical formula of CH4O and a molar mass of 32 g/mol has a molecular formula of: Great work! That's correct. CH4O C2H8O2 C2H4O2 C3H8O3

CH4O The empirical formula weight is 32 g/mol so the molar mass divided by that is 3232=1. This means the molecular formula is the same as the empirical formula.

Which of the following is the chemical symbol for carbon monoxide? The carbon monoxide compound contains one carbon and one oxygen atom. CO co Co cO

CO 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 could Antoine Lavoisier, the French scientist credited with proposing the law of conservation of matter, have demonstrated this law? ! Carefully measuring the mass of reactants before a reaction and the mass of the products after a reaction in a sealed system Burning wood to show that both ash and smoke are produced Proving E=mc2 to demonstrate that mass can be converted into energy Discovering the existence of anti-matter

Carefully measuring the mass of reactants before a reaction and the mass of the products after a reaction in a sealed system Antoine Lavoisier is credited with proposing the law of conservation of matter. He performed experiments where he meticulously measured the masses of reaction reactants and products in a sealed system, so that no gas could escape. His demonstration that the mass of the reactants was equal to the mass of products supported the law of conservation of matter.

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

Chemistry is highly interconnected with so many other scientific disciplines.

A small snail makes a journey that takes him in a circle of area 0.750square meters in one day. What is the area of the circle that the snail makes in square inches? Round to three significant figures. Do not give the units in your answer. Use the conversion factor 1 inch=2.54 centimeters.

Convert square meters to square centimeters, and then to square inches. Use the squared conversion factor in each case. There are 100 centimeters in a meter and 2.54 centimeters in an inch. Multiply 0.750m2 by (100cm/m)2 and then by (1in.2.54cm)2. Note that the conversion factors must be squared because square meters are converted to square centimeters and then square centimeters are converted to square inches. 0.750m2×(100cm/m)2×(1in.2.54cm)2=1,160in.2

How many total atoms are present in 400 grams of Na2SO4? 1.19×1025 atoms 1.71×1024 atoms 2.33×1025 atoms 1.60×1025 atoms

Correct answer: 1.19×1025 atoms First calculate the number of formula units of Na2SO4 by multiplying the number of moles by Avogadro's number. 400. g×1 mol Na2SO4142.042 g×6.022×1023 formula unitsmol≈1.696×1024 formula units There are 2 sodium atoms, 1 sulfer atom, and 4 oxygen atoms in each formula unit of Na2SO4, for a total of 2+1+4=7 atoms per formula unit. 1.696×1024 formula units×7 atoms formula unit of Na2SO4≈1.187×1025 atoms The correct answer should have three significant figure, so round to 1.19×1025 atoms

How many grams of iron contain 4.06×1024atoms of iron? Use 6.022×1023atomsmole for Avogadro's number. 6.74g 377g 0.121g 8.28g

Correct answer: 377g Dividing the number of atoms by Avogadro's number yields the number of moles. Multiplying the number of moles by molar mass yields mass (number of grams). 4.06×1024atomsFe×1molFe6.022×1023atomsFe×55.845gFe1molFe=377gFe

Ammonium nitrite (NH4NO2) has a percent composition of _______ for oxygen.

Correct answer: 50% Calculate formula mass: 2(14)+2(16)+4(1)=64 g/mol Calculate percent composition of oxygen: 32 g/mol64 g/mol=50% O

A compound has a percent composition of 52% C, 13% H, and 35% O.What is the empirical formula?

Correct answer: C2H6O Let the mass percents from the percent composition represent grams in a total mass of 100g. Use the grams to calculate the number of moles of each atom present. %C=52%=52gC molC=52gC×1molC12.011gC=4.3molC %H=13%=13gH molH=13gH×1molH1.008gH=13molH %O=35%=35gO molO=35gO×1molO15.999gO=2.2molO Divide by the smallest number of moles. subscriptC=4.3molC2.2molO=2 subscriptH=13molH2.2molO=6 subscriptO=2.2molO2.2molO=1 The empirical formula is C2H6O.

A 150 g sample of a compound is comprised of 44.07% C, 8.98% H and the remainder is O by mass. What is the compound's empirical formula? Correct! You nailed it. CHO C5H12O4 C4H8O3 C1H2O2

Correct answer: C5H12O4 You can determine the percent oxygen by acknowledging that the percentage of all three elements must add up to 100%. Therefore, the percent oxygen is 100%−44.07%−8.98%=46.95% To determine the empirical formula, first you need to convert percents to masses: 0.4407×150 g=66.105 g C0.0898×150 g=13.47 g H0.4695×150 g=70.425 g O Use the grams to calculate the number of moles of each atom present. molC=66.105gC×1molC12.011gC=5.50molC molH=13.47gH×1molH1.008gH=13.36molH molO=70.425gO×1molO15.999gO=4.40molO Divide by the smallest number of moles. subscriptC=5.50molC4.40molO=1.25 subscriptH=13.36molH4.40molO=3 subscriptO=4.40molO4.40molO=1 Multiplying by four to get whole numbers, the answer is: C5H12O4.

A compound consists of 37.51 g C, 4.20 g H, and 58.29 g O. What is the empirical formula? Perfect. Your hard work is paying off 😀 CHO C2H3O2 C3H4O2 C6H8O7

Correct answer: C6H8O7 First, use the grams to calculate the number of moles of each atom present. molC=37.51gC×1molC12.011gC=3.123molC molH=4.20gH×1molH1.008gH=4.167molH molO=58.29gO×1molO15.999gO=3.643molO Next, divide by the smallest number of moles. subscriptC=3.123molC3.123molC=1 subscriptH=4.167molH3.123molC=1.334≈43 subscriptO=3.643molO3.123;molC=1.166≈76 Notice that the value obtained for oxygen is approximately equal to 76; therefore, multiplying each of the values above by 6 will yield the whole number subscripts to be used in the empirical formula. Subscript C:1×6=6Subscript H:43×6=8Subscript O:76×6=7 Therefore, the empirical formula is C6H8O7.

A sample of a compound is made up of 57.53 g C, 3.45 g H, and 39.01 g F. Determine the empirical formula of this compound. Perfect. Your hard work is paying off 😀 CHF C7H5F3 C2H3F2 CHF5

Correct answer: C7H5F3 First, use the grams to calculate the number of moles of each atom present. molC=57.53gC×1molC12.011gC=4.790molC molH=3.45gH×1molH1.008gH=3.423molH molF=39.01gF×1molF18.998gF=2.053molF Next, divide by the smallest number of moles. subscriptC=4.790molC2.053molF=2.33≈73 subscriptH=3.423molH2.053molF=1.66≈53 subscriptF=2.053molF2.053molF=1 Notice that the values obtained for carbon and hydrogen are approximately equal to 73 and 53 respectively; therefore, multiplying each of the values above by 3 will yield the whole number subscripts to be used in the empirical formula. Subscript C:73×3=7Subscript H:53×3=5Subscript F:1×3=3 Therefore, the empirical formula is C7H5F3.

A compound has a mass percentage of 53.46% C, 6.98% H, and 39.56% O. What is the empirical formula for this compound? Perfect. Your hard work is paying off 😀 CH5O3 C2H5O3 C9H14O5 CHO

Correct answer: C9H14O5 Let the mass percents from the percent composition represent grams in a total mass of 100g. Use the grams to calculate the number of moles of each atom present. %C:53.46%molC=53.46gC=53.46gC×1molC12.011gC=4.451molC %H:6.98%molH=6.98gH=6.98gH×1molH1.008gH=6.924molH %O:39.56%molO=39.56gO=39.56gO×1molO15.999gO=2.473molO Divide by the smallest number of moles. subscriptC=4.451molC2.473molO≈1.800≈95 subscriptH=6.924molH2.473molO≈2.800≈145 subscriptO=2.473molO2.473molO=1 Now, multiply each subscript by 5 to achieve whole number subscripts. Therefore, the empirical formula is C9H14O5.

After a reaction, a new compound contains 0.73 g Mg and 0.28 g N. What is the empirical formula of this compound?

Correct answer: Mg3N2 First, use the grams to calculate the number of moles of each atom present. molMg=0.73gMg×1molMg24.305gMg=0.030molMg molN=0.28gN×1molN14.007gN=0.020molN Next, divide by the smallest number of moles. subscriptMg=0.030molMg0.020molN=1.5 In order to get a whole number we must multiply by 2, subscriptMg=3 subscriptN=0.020molN0.020molN=1 In order to stay consistent we must multiply by 2, subscriptN=2 The empirical formula is Mg3N2.

A compound is made up of 28 g N, 24 g C, 48 g O, and 8 g H. What is the empirical formula? Correct! You nailed it. NCHO N3CH4O4 N2C2H8O3 NCH3O2

Correct answer: N2C2H8O3 First convert the mass of each type of atom to moles using the atomic masses from the periodic table. N=28g14g/mol=2molC=24g12g/mol=2molO=48g16g/mol=3molH=8gg/mol=8mol These ratios can be used to construct the empirical formula because there are no common factors between them (3 is a prime number). Thus, the empirical formula is N2C2H8O3 .

Which of the following correctly pair the polyatomic ion with its formula? Select all that apply. cyanide, CN− chlorate, ClO−3 sulfate, SO− nitrate, NO−3

Correct answer: cyanide, CN− chlorate, ClO−3 nitrate, NO−3 The only ion that is incorrectly named is sulfate. The formula for sulfate is SO2−4. All of the other answer choices correctly pair the polyatomic ions with their formulas.

Iridium has two stable isotopes: 191Ir and 193Ir with masses of 190.9605940 amu and 192.9629264 amu. If the fractional abundance of 191Ir is 0.373 on Earth, complete the expression below that can be used to calculate the average atomic mass. Your answers should have three significant figures.

Correct answers:$(0.373)(190.9605940)+(0.627)(192.9629264)$(0.373)(190.9605940)+(0.627)(192.9629264)​ The formula for finding the average atomic mass requires the precise mass and fractional abundance of each isotope. The fractional abundance of 191Ir is given (0.373). To find the fractional abundance of 193Ir, note that the sum any element's isotopic abundances is 1. Since 193Ir is the only other stable isotope of irridium, it can be found by subtracting the abundance of 191Ir from 1. 0.373+xx=1=1−0.373=0.627 Substitute the fractional abundances of each isotope into the expression so that the mass of each isotope is multiplied by the fractional abundance of that isotope. (0.373)(190.9605940)+(0.627)(192.9629264)

Copper has two stable isotopes, 63Cu and 65Cu, with masses of 62.9295975 amu and 64.9277895 amu. If the average atomic mass for copper on Earth is 63.546 amu, what is the fractional abundance of the most common isotope? Hint: Set the abundance of the most abundant isotope equal to x. Then the abundance of the other isotope will equal 1−x. Express your answer as a decimal between 0 and 1. Round to four significant figures (four decimal places).

Correct answers:$0.6915$0.6915​ The average mass is closer to 63Cu, so let x represent the abundance of that isotope. Set up an equation expressing the average mass in terms of x and solve. 62.9295975x+64.9277895(1−x)(62.9295975−64.9277895)xxx=63.546=63.546−64.9277895=63.546−64.927789562.9295975−64.9277895=0.6915199 The answer should have four significant figures, so round to 0.6915. Therefore, the most abundant isotope is 63Cu with a fractional abundance of 0.6915.

How many atoms of Bi are there in a 41.8 g sample? Use 6.022×1023mol−1 for Avogadro's number. Report your answer in scientific notation using the multiplication symbol, ×, not the letter x. Your answer should have three significant figures.

Correct answers:$1.20\times10^{23}\text{ atoms}$1.20×1023 atoms​ First, convert the mass of bismuth into moles by dividing by the molar mass of bismuth found on the Periodic Table: 41.8 g×1 mol Bi208.980 g Bi=0.20002 mol Recall that Avogadro's number describes the number of atoms or molecules in a mole. By dimensional analysis, we see that we can convert the moles of bismuth into atoms by multiplying the moles of bismuth by Avogadro's number: 0.20002 mol Bi×6.022×1023 atoms1 mol=1.2045×1023 atoms The answer should have three significant figures, so round to 1.20×1023 atoms.

The formula of nitric acid is HNO3. Determine the percent composition of hydrogen in this compound. Round your answer to three decimal places.

Correct answers:$1.600\text{%}$1.600%​ First, calculate the formula mass for the entire compound: formula mass of HNO3formula mass of HNO3formula mass of HNO3=1×(molar mass of H)+1×(molar mass of N)+3×(molar mass of O)=1×(1.008gmol)+1×(14.007gmol)+3×(15.999gmol)=63.012gmol Next, divide the mass of the H atom by the mass of the entire compound and multiply by 100: %H=1.008gmolH63.012gmolHNO3×100=1.600%H

Silver has two stable isotopes: 107Ag with a fractional abundance on earth of 0.51839 and 109Ag with a mass of 108.904752 amu. If the average atomic mass for silver on Earth is 107.8682 amu, what is the mass of the most common isotope? Your answer should have four significant figures (round to the nearest tenth)

Correct answers:$106.9\text{ amu}$106.9 amu​ The fractional abundance of 107Ag is greater than 0.5, so it is the most abundant isotope. Let x represent the mass of that isotope. Set up an equation expressing the average mass in terms of x and solve. Multiply the fractional abundance of each isotope by its mass and set the sum of the products equal to the average mass. The fractional abundance of 107Ag is 0.51839 and that of 109Ag is 1−0.51839since there are only two isotopes. 0.51839x+108.904752(1−0.51839)xx=107.8682=107.8682−108.904752(1−0.51839)0.51839=106.905 The answer should have four significant figures, so round to 106.9 amu.

A mole is equivalent to the number of atoms in _______ grams of carbon-12. Report your answer as a whole number without any decimal places.

Correct answers:$12$12​ A mole is equivalent to the number of atoms in 12 grams of carbon-12. This exact number was found to be 6.022×1023 atoms .

What is the formula mass of a compound with 2 aluminum atoms, 3 sulfur atoms, and 3 oxygen atoms, in atomic mass units? Your answer should have six significant figures.

Correct answers:$198.159\text{ amu}$198.159 amu​ Use the periodic table to get the atomic mass of each element. Multiply the atomic mass of the element by the number of atoms of that element in the compound. mass of Al: 26.982×2=53.964 mass of S: 32.066×3=96.198 mass of O: 15.999×3=47.997 Add the mass of each element to find the total.

How many sulfur atoms are there in 5.325×10−23 grams of sulfur? Use 6.022×1023mol−1 for Avogadro's number. Your answer should be a whole number without any decimal places.

Correct answers:$1\text{ atoms}$1 atoms​ First, convert the mass of S into moles by dividing by the molar mass of Sfound on the Periodic Table: 5.325×10−23 g×1 mol S32.066 g=1.6606×10−24 mol Recall that Avogadro's number describes the number of atoms or molecules that make up a mole. By dimensional analysis, we see that we can convert moles into atoms by multiplying the moles of S by Avogadro's number: 1.6606×10−24 mol×6.022×1023atoms1 mol=1.00004 atom Since there can only be a whole number of atoms, the rounded answer of 1 atom can be treated as exact.

Out of 200 neon atoms, 170 will be neon-20(19.992 amu) and 30will be neon-22(21.991 amu). What is the average atomic mass of neon, in amu? Round your answer to three decimal places.

Correct answers:$20.292\text{ amu}$20.292 amu​ The average atomic mass of neon is a weighted average. First, we need to calculate the fraction of the sample that is composed of Ne-20, and the fraction of the sample that is Ne-22: 170 atoms of Ne-20200 total atoms=0.8530 atoms of Ne-22200 total atoms=0.15 The sample is 85% Ne-20 and 15% Ne-22. To find the weighted average mass of the neon sample (which is equal to the average atomic mass of neon), we simply scale the mass of each isotope by its percentage in the sample expressed as a decimal, and add the weighted masses together: (0.85×19.992 amu)+(0.15×21.991 amu)=20.292 amu As we might expect, the average atomic mass of neon is much closer to 20 amu than to 22 amu, given that the neon sample is mostly Ne-20.

A 16.22 g sample contains 4.82 g F, 4.91 g H, and 6.49 g C. What is the percent composition of fluorine in this sample? Your answer should have three significant figures.

Correct answers:$29.7\text{%}$29.7%​ Divide the mass of fluorine in the sample by the mass of the entire sample and then multiply by 100 to get your final percent. %F=4.82 g16.22 g×100%=29.7% F

A sample of sulfur trioxide (SO3) weighs 5100 g. How many molecules are contained in this sample? Use 80.063gmol for the molar mass of SO3. Use 6.022×1023mol−1 for Avogadro's number. Report your answer in scientific notation using the multiplication symbol, ×, not the letter x. Your answer should have two significant figures.

Correct answers:$3.8\times10^{25}\text{ molecules}$3.8×1025 molecules​ First, convert the mass of SO3 into moles of SO3 by dividing by the molar mass: 5100 g×1 mol SO380.063 g SO3=63.70 mol Recall that Avogadro's number describes the number of atoms or molecules in a mole. By dimensional analysis, we see that we can convert the moles of SO3 into molecules by multiplying the moles of SO3 by Avogadro's number: 63.70 mol×6.022×1023 molecules1 mol=3.836×1025 molecules The answer should have two significant figures, so round to 3.8×1025 molecules.

What is the mass in grams of 1.00×1023 radon atoms? Use 6.022×1023mol−1 for Avogadro's number. Your answer should have three significant figures.

Correct answers:$36.9\text{ g}$36.9 g​ Recall that Avogadro's number gives the number of atoms or molecules that make up a mole. By dimensional analysis, we see that we can convert the number of atoms into moles by dividing by Avogadro's number: 1.00×1023 atoms×1 mol6.022×1023 atoms=0.1661 mol Next, convert the moles of radon atoms into grams, using the molar mass found on the Periodic Table: 0.1661 mol×222.018 g1 mol=36.9 g

A 16.20 g sample contains 4.80 g F, 4.90 g H, and 6.50 g C. What is the percent composition of carbon in this sample? Your answer should have three significant figures.

Correct answers:$40.1\text{%}$40.1%​ Divide the mass of carbon in the sample by the mass of the entire sample and then multiply by 100 to get your final percent. %C=6.50 g16.20 g×100%=40.1% C

A compound that weighs 56.2 g contains 23.6 g Sb (antimony) and 32.6 g F (fluorine). What is the percent composition of antimony? Your answer should have three significant figures.

Correct answers:$42.0\text{%}$42.0%​ Divide the mass of antimony in the sample by the mass of the entire sample and then multiply by 100 to get your final percent. %Sb=23.6 g56.2 g×100%=42.0% Sb

How many barium atoms are in a 9.8×10−21 gram sample? Use 6.022×1023 atoms per mole for Avogadro's number. Your answer should have two significant figures.

Correct answers:$43\text{ atoms}$43 atoms​ First, convert the grams of Ba into moles by dividing the mass of Ba by the molar mass found on the Periodic Table: 9.8×10−21 g×1 mol137.328 g=7.1362×10−23 mol Recall that Avogadro's number describes the number of atoms or molecules in a mole. By dimensional analysis, we see that we can convert the moles of Ba into atoms by multiplying the moles of Ba by Avogadro's number: 7.1362×10−23 mol×6.022×1023 atoms1 mol=42.974 atoms Since answer should have two significant figures, write it as 43 atoms.

Calculate the number of atoms in 37.1 grams of LiBr. Use 6.022×1023mol−1 for Avogadro's number. Report your answer in scientific notation, using the multiplication symbol, ×, not the letter x. Your answer should have three significant figures.

Correct answers:$5.15\times10^{23}\text{ atoms}$5.15×1023 atoms​ Keep in mind that you need to multiply the number of formula units of LiBr, calculated using Avogadro's number, by the number of atoms in each formula unit (2). 37.1 g(1 mol LiBr86.844 g LiBr)(6.022×1023 formula unitsmol)=2.573×1023 formula units 2.573×1023 formula units(2 atomsformula unit of LiBr)=5.146×1023 atoms Therefore, after rounding the answer to three significant figures, we find that there are 5.15×1023atoms in 37.1g of LiBr.

What is the average mass of lithium, in amu, if 92.41% exists as 7Li (7.016 amu) and 7.59% exists as 6Li (6.015 amu)? Your answer should have four significant figures.

Correct answers:$6.940\text{ amu}$6.940 amu​ To find the weighted average mass of lithium (which is equal to the average atomic mass of Li), we simply scale the mass of each isotope by its percentage, expressed as a decimal, and add the weighted masses together: (0.9241×7.016 amu)+(0.0759×6.015 amu)=6.940 amu Note that the average atomic mass of Li is much closer to 7 amuthan 6 amu; this makes sense given that the vast majority of lithium is present as 7Li.

Find the percent composition of lithium (Li) in lithium bromide (LiBr). Round your answer to two decimal places.

Correct answers:$7.99\text{%}$7.99%​ First, calculate the formula mass for the entire compound: formula mass of LiBrformula mass of LiBrformula mass of LiBr=1×(molar mass of Li)+1×(molar mass of Br)=1×(6.94gmol)+1×(79.904gmol)=86.844gmol≈86.84gmol Next, divide the mass of the Li atom by the mass of the entire compound and multiply by 100: %Li=6.94gmolLi86.844gmolLiBr×100=7.99%Li

Oxalic acid's molecular formula is C2H2O4. What is its empirical formula?

Correct answers:$CHO_2$CHO2​​ The empirical formula must feature the simplest whole-number ratio of the constituent elements. The simplest form of the carbon: hydrogen: oxygen ratio, given as 2:2:4, is 1:1:2. Therefore, the empirical formula is CHO2.

A molecule of pentene consists of 5 carbon atoms and 10 hydrogen atoms. What is pentene's molecular formula?

Correct answers:$C_5H_{10}$C5​H10​​ Pentene's molecular formula is C5H10 because it represents the actual number of atoms in the compound (as given in the question text).

What is the chemical formula for the polyatomic ion Chlorate?

Correct answers:$ClO_3^-$ClO−3​​ The chlorate ion is an anion with the formula ClO−3. This is a polyatomic ion that must be memorized. Be careful not to confuse it with the chlorite ion which has the formula ClO−2.

What is the formula for lithium phosphate?

Correct answers:$Li_3PO_4$Li3​PO4​​ Step 1: Identify the symbol of the cation.Result of this step = Li+. Step 2: Identify the formula of the anion.Result of this step = PO3−4. 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 = Li+ has a 1+ charge and PO3−4 has a 3− charge, which do NOT equate to zero. In order to balance the charges, you need three Li+ for every one PO3−4 . The resulting formula of this compound is Li3PO4.

A molecule of dinitrogen tetroxide consists of 2 nitrogen atoms and 4 oxygen atoms. What is dinitrogen tetroxide's empirical formula?

Correct answers:$NO_2$NO2​​ The empirical formula must feature the simplest whole-number ratio of the constituent elements. The simplest form of the nitrogen: oxygen ratio, given as 2:4, is 1:2. Therefore, the empirical formula is NO2

Sodium bicarbonate is formed from the Na+ cation and the HCO−3 anion. What is the correct formula for this compound?

Correct answers:$NaHCO_3$NaHCO3​​ An ionic compound must be electrically neutral, so it must have the same number of positive and negative charges. One sodium ion with a charge of 1+, gives us one positive charge, while one bicarbonate ion, with a charge of 1−, gives us one negative charge. Therefore, the formula is a 1:1 ratio of sodium to bicarbonate, NaHCO3.

Sulfur hexafluoride has the formula

Correct answers:$SF_6$SF6​​ Sulfur hexafluoride is SF6 because the name indicates 1 sulfur atom and the prefix "hexa-" indicates 6 fluorine atoms.

Write the correct 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. Be sure to use the periodic table to identify the correct atomic symbol, which should be used in the answer.

Correct answers:$_{54}^{132}Xe$13254​Xe​ 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 13254Xe.

Which element has an atomic number of 29? Yes that's right. Keep it up! Cu Ni Si P

Cu Copper has an atomic number of 29. This number is found in the top left corner of the element block and represents the number of protons in the element.

Which of the following is the correct formula for the ionic compound: copper (I) fluoride? 2CuF Cu3F CuF CuF2

CuF Copper (I) fluoride is CuF.

Which of the following are involved in the study of chemistry? A. the motion of planets in outer space B. the structure and function of organs in living systems C. the interactions between energy and matter D. The changes in the composition and structure of matter

D. The changes in the composition and structure of matter

Chemistry provides a basis for all of the following EXCEPT? A. medicine B. cleaning products C. environmental science D. astrology

D. astrology

Which of the following is not reliant on an understanding of chemistry? A. geology B. biotechnology C. agriculture D. mathematics

D. mathematics

What is significant about the temperature of 0K? It is the temperature at which matter has no density. It is the temperature at which atoms stop moving. It is the temperature at which atoms cease to exist. It is the temperature at which water molecules freeze.

It is the temperature at which atoms stop moving.

Which of the following must be true about a precise measurement? It typically contains many significant figures. It has very few significant figures. It is very close to the true value. It is far away from the true value.

It typically contains many significant figures.

Jamie is measuring the mass of one mole of carbon. She measures the mass 4 times, achieving the following measurements: 11.86 g, 11.87 g, 11.89 g, and 11.90 g. If the accepted value of one mole of carbon is 12.11 g, how can Jamie's measurements best be described? Jamie's measurements are both precise and accurate. Jamie's measurements are accurate but not precise. Jamie's measurements are precise but not accurate. Jamie's measurements are neither precise nor accurate.

Jamie's measurements are precise but not accurate.

If a compound has a formula mass of 212, the chemical formula could be: Na2SO4 K2SO4 Na3PO4 K3PO4

K3PO4 Use the periodic table to get the atomic masses of each element. Then you can calculate the formula mass as such: K=39.098×3=117.294 P=30.974×1=30.974 O=15.999×4=63.996 Adding these together we get 212.264, which is approximately 212 amu.

The periodic table of elements is above for your reference. Which of the following is NOT a chemical symbol? C Kr NO Zn

NO NO is not a chemical symbol. NO refers to a molecule of nitrogen monoxide, comprised of one atom of nitrogen and one atom of oxygen. Thus NO is a molecular formula, not a chemical symbol. Do not confuse this molecule with the element nobelium, abbreviated as No.

If a compound has a formula mass of 62, the chemical formula could be: Correct! You nailed it. Na2O CaO KF MgO

Na2O Use the periodic table to get the atomic masses of each element. Then you can calculate the formula mass as such: Na=22.990×2=45.980O=15.999×1=15.999 Adding these together we get 61.979, which is approximately 62 amu.

If a compound has a formula mass of 40, the chemical formula could be: Yes that's right. Keep it up! MgF2 NaOH NaF KF

NaOH Use the periodic table to get the atomic masses of each element. Then you can calculate the formula mass as such: H=1.008×1=1.008Na=22.990×1=22.990O=15.999×1=15.999 Adding these together we get 39.997, which is approximately 40 amu.

Which of the following events fail to follow the law of conservation of matter? Well done! You got it right. Burning wood for a fire Freezing water into ice cubes The decomposition of MgCl2 into Mg and Cl2 None of thes

None of these All of these events follow the law of conservation of matter.

Which of the following is a rule of significant figures in calculations? Round the result to the same number of digits as the number with the most number of significant figures. Round up if the digit to be dropped is less than 5. Round down if the digit to be dropped is less than 5. None of the above.

Round down if the digit to be dropped is less than 5. We round down if the digit to be dropped is less than 5. For example, to round the value 2.443 to three significant figures, we round down to 2.44 because the digit to be dropped (3) is less than five.

Haley finds that a compound has a molar mass of 64.07 g/mol and an empirical formula of SO2. What is the molecular formula of this compound? Great work! That's correct. SO SO2 SO4 S2

SO2 The empirical formula weight is 64 g/mol so the molar mass divided by this is 64.07/64=1. This means the molecular formula is the same as the empirical formula.

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?

The density is 9.0gcm3, and the block is copper.

How is it possible that energy is always conserved, but we are always saying we need to "conserve more energy"? The total amount of energy in any process varies. The total amount of energy in any process decreases. The total amount of energy in any process is fixed. The total amount of energy in any process increases.

The total amount of energy in any process is fixed. When we say energy is always conserved we mean the total amount of energy in any process or reaction never changes - it is fixed. When we tell ourselves to conserve energy we mean to use less of it by doing things like driving more fuel efficient cars, or insulating our houses better.

Which of the following is a correct statement about different elements that are in the same group in the periodic table? They have the same atomic number. They have different chemical properties. They are in the same column of the periodic table. They are in the same row of the periodic table.

They are in the same column of the periodic table. 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.

What will weigh more when a chemical reaction is complete: the reactants before the reaction or the products after the reaction is complete? They both will weigh the same. The products will weigh more than the reactants. The reactants will weigh more than the products. They both will lose mass during the reaction.

They both will weigh the same. According to the law of conservation of matter: there is no detectable change in the total amount of matter during a chemical change. When chemical reactions occur, the energy changes are relatively modest, and the mass changes are too small to measure, so the laws of conservation of matter states that the amount of matter before and after a chemical reaction are always the same.

Mercury has a density of 13.56 g per cubic centimeter. Convert the density to kilograms per cubic meter.

This problem requires using two different conversions: grams to kilograms and centimeters to meters. Since the starting units have grams in the numerator, use the conversion factor 1 kg1000 gto obtain kilograms in the numerator. The starting units have cubic centimeters in the denominator, so use the cubed conversion factor (100 cm1 m)3 to obtain cubic meters in the denominator. 13.56 gcm3×1 kg1000 g×(100 cm1 m)3=13560 kgm3

The speed of light is around 6.706×108 miles per hour. What is the speed of light in units of miles per minute? Round the answer to four significant figures. Enter the answer in scientific notation.

To find the speed of light in units of miles per minute, we must use the fact that 60min=1hr. 6.706×108mihr×1hr60min=1.118×107mimin Therefore, we find that the speed of light is approximately 1.118×107 miles per minute.

Which of the following substances will take the shape of a container it is placed in?

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.

Which of the following statements is true regarding weight and mass? Mass is the amount of force that gravity exerts on an object. Weight is the amount of matter an object has. Mass of an object is not constant. Weight is dependent on a source of gravity.

Weight is dependent on a source of gravity.

Which of the following questions is the best example of a question that could be answered or explained by studying chemistry? A. Which part of the country has the most salt-water lakes? B. What is the identity of this unknown substance? C. What is the angle of refraction when light enters water? D. What is the acceleration of a race car in meters/second?

What is the identity of this unknown substance?

A child on a sled starts at the top of a hill with 90 J of potential energy. At the bottom of the hill, she has only 55 J of kinetic energy. Assuming that at the top of the hill she has only potential energy and at the bottom she has only kinetic energy, what can we conclude? (Remember, potential energy is the energy of position while kinetic energy is the energy of motion.) Work must have been done. The child is not good at sledding. At some point, the child hesitated going down the hill. The child sleds down one hill but is about to go up another hill.

Work must have been done. There was a change in the amount of energy so work must have been done. Motion is definitely indicated which shows work has been accomplished. The other 3 choices are assumptions which cannot be empirically obtained in this problem.

What is the result of two or more atoms forming chemical bonds with each other?

a molecule

The reason that atomic numbers are always integer values is because every element has: a particular number of neutrons a particular number of electrons a particular number of protons a particular atomic mass

a particular number of protons The atomic number refers to the number of protons in an atom, which is always a specific number for a given element.

If something is a compound, it is also __________ . an element a pure substance a mixture a single atom

a pure substance Pure substances are either elements or compounds. A compound is a pure substance composed of more than one element. A compound is not a mixture because mixtures can be separated by physical means. Since a compound is composed of more than one type of atom, it cannot be a single atom.

Which is the longest distance? a meter a kilometer a megameter a terameter

a terameter

Which is an example of a homogeneous mixture? air breakfast cereal soil oxygen

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

The group that is least likely to ionize is the __________. alkali metals transition metals halogens noble gases

alkali metals These are the elements in the first group of the periodic table. They tend to have a charge of 1+ when ionized.

Which of the following is an example of a physical property? boiling point melting point color all of the above

all of the above Boiling point, melting point, and color are all considered physical properties.

The symbol Fe could refer to which of the following? Select the bestanswer below. Select the correct answer below: an iron atom The element known as "iron." a macroscopic sample of iron all of the above

all of the above 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. Your answer: The element known as "iron."

Neutral nonmetal atoms typically gain electrons, thus becoming __________. anions cations polar neutral

anions Nonmetals typically gain electrons to form negatively charged ions, also called anions.

Which of the following gives all of the information necessary to determine the number of subatomic particles? mass number atomic number atomic symbol element name

atomic symbol 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? flammability reactivity boiling point toxicity

boiling point 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.

During a __________ process, the identity of the molecule ___________. chemical; does not change chemical ; changes physical; changes None of the above

chemical ; changes During a chemical process, the identify of the molecule changes. A chemical change always produces one or more types of matter that differ from the matter present before the change.

Rank the following polyatomic ions from fewest to most oxygen atoms: 1. Chlorate 2. Chlorite 3. Perchlorate

chlorite, chlorate, perchlorate The correct order from fewest to most oxygen atoms for these polyatomic ions is as follows: chlorite, chlorate, and perchlorate. Recall that -ate and -ite are the suffixes used to designate polyatomic ions containing more and fewer oxygen atoms, respectively. Per- (short for "hyper") and hypo- (meaning "under") are prefixes signifying even more oxygen atoms than -ate and even fewer oxygen atoms than -ite, respectively. Therefore, ClO−2 is the formula for chlorite, ClO−3 is the formula for chlorate and ClO−4 is the formula for perchlorate.

Which of the following could be considered a chemical change? dew condensing on a leaf mixing sugar in with your tea coal burning water evaporating from a pond on a hot day

coal burning Phase changes and mixing of substances are physical processes. When coal burns, carbon atoms form new chemical bonds to oxygen atoms, which is a chemical process.

The charges on the proton and electron are typically measured in: volts amperes coulombs daltons

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

Where would you be "weightless"?

deep space Only in deep space, far away from any source of gravity, would there be no gravitational force to give your body any weight. You would still have mass, but you would be effectively weightless.

Using the strict IUPAC naming convention for binary molecular compounds, the name for water (H2O) would be __________. Well done! You got it right. hydrogen oxide dihydrogen oxide hydrogen monoxide dihydrogen monoxide

dihydrogen monoxide Here, we will need to specify with prefixes that there are two hydrogen atoms and one oxygen atom.

Different ions of a given element will have differing numbers of __________. Correct! You nailed it. protons neutrons electrons molecular formulas

electrons Ions and neutral atoms of the same element differ by having different numbers of electrons. For example, silver has both a +1 and a +2 cation with 46 and 45 electrons, respectively.

An alternative name for iron(II) chloride is: Yes that's right. Keep it up! iron chloride ferrous chloride ferric chloride ferrum chloride

ferrous chloride The word ferrous implies the Fe2+ ion.

Au2O3 is called: Yes that's right. Keep it up! gold oxide gold(II) oxide gold(III) oxide gold(IV) oxide

gold(III) oxide We must specify the oxidation state of the gold atoms, and if oxygen is 2−, gold must be 3+, hence the roman numeral III.

Precision

how closely a measurement matches the same measurement when repeated

The noble gases are also called the: reactive gases inert gases lonely gases none of the above

inert gases Nobel gases are also known as inert gases because they are for the most part completely unreactive.

IF7 is called iodine hexafluoride. monoiodine hexafluoride. iodine heptafluoride. monoiodine heptafluoride.

iodine heptafluoride. We don't need a prefix for iodine, but fluoride will need the prefix "hepta," indicating there are seven of them.

Which of the following correctly pairs the ion name with the ion symbol? Great work! That's correct. iodine, I− sulfite, S2− lithium cation, Li+ nitride, N−

lithium cation, Li+ The correct pairing of the monoatomic ion with its formula is lithium ion with Li+.

The ion Na+ has a 1+ charge gained an electron This means this element has __________. lost an electron gained a proton lost a proton

lost an electron 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.

MgCl2 is called __________. magnesium dichloride magnesium chlorate monomagnesium chlorate magnesium chloride

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

MgSO3 is called ___________. Correct! You nailed it. magnesium sulfate magnesium sulfide magnesium sulfur oxide magnesium sulfite

magnesium sulfite Because SO2−3 has one fewer oxygen than a sulfate ion, it is called a sulfite ion, hence magnesium sulfite.

For a given atom, which of the following is typically the largest in value? atomic number number of protons mass number all of the above are typically equal

mass number 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: atomic numbers numbers of protons mass numbers none of the above

mass numbers 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.

Elements in group 2 are: metalloids metals nonmetals all of the above

metals All elements in group 2 are metals. Metals are elements that are shiny, malleable, good conductors of heat and electricity.

When naming binary covalent compounds, the element listed first will be the one that is Great work! That's correct. more metallic. less metallic. heavier. lighter.

more metallic. The atom farther to the left on the periodic table, which will be the one with more metallic character, will be listed first.

To convert moles of an atom to grams you must ______________ the molar mass. Perfect. Your hard work is paying off 😀 divide by multiply by add subtract

multiply by To convert moles of an atom to grams, you must multiply by the molar mass. For example, to convert 0.12 mol of potassium (K) to grams, you would need to multiply by the molar mass of K. Referring to the periodic table, the molar mass of K is 39.098g/mol. Therefore, the equation to convert mol to g would be: 0.12molK×39.098gK1molK=4.7gK

When an atom gains electrons, it becomes a __________. Great work! That's correct. negatively charged ion, known as an anion negatively charged ion, known as a cation positively charged ion, known as an anion positively charged ion, known as a cation

negatively charged ion, known as an anion 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.

The idea that elements exhibit recurring properties is called: Perfect. Your hard work is paying off 😀 recurrence chemical law periodic law none of the above

periodic law Periodic law highlights the periodicity, or recurring properties, of the elements.

The mass number is essentially the sum of the number of ________ in an atom. protons and electrons neutrons and electrons protons and neutrons protons and neutrons and electrons

protons and neutrons 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.

An example of homogeneous mixture is: muddy water pure water ice water saline water

saline water A homogeneous mixture has uniform composition for any given sample. A saline water solution has equal parts of salt dissolved throughout. Muddy water and ice water are heterogenous mixtures while pure water is a compound (and a pure substance).

What is another word for period? Correct! You nailed it. series group section family

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

Which of the following is named using the unmodified element name and adding the word "ion"? Well done! You got it right. simple cations (monatomic cations of elements of only one possible charge) simple anions (monatomic anions of elements of only one possible charge) simple protons simple neutrons

simple cations (monatomic cations of elements of only one possible charge) Simple cations are named with their elemental name followed by the word "ion." For instance, Na+ is named the sodium ion.

Which of the following is NOT a physical property of a bronze coin? that it is shiny that it is hard and durable that it will slowly change color over many years that it sinks in water

that it will slowly change color over many years 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.

What does the "2" represent in the formula for a water molecule (H2O)? Well done! You got it right. that there are two oxygen atoms that there are two hydrogen atoms that there are two oxygen and two hydrogen atoms that there are two molecules of water

that there are two hydrogen atoms The two applies to hydrogen. It means there are two hydrogen atoms per water molecule.

Which of the following is NOT a likely indicator of a chemical change? the formation of a precipitate a color change the change in shape of a malleable metal the release of gas without adding heat or lowering the pressure

the change in shape of a malleable metal The bending of a piece of metal, like a paper clip, is not a chemical change. Only when a new substance is formed, evidenced by a new material present or a change in color, can a chemical change be guaranteed.

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

the chemical symbol 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.

The sum of the average atomic masses of all the atoms present in a substance's formula is known as: Correct! You nailed it. the atomic mass the formula mass (molecular mass) an atomic mass unit the mass number

the formula mass (molecular mass) The sum of the average atomic masses of all the atoms present in a substance's formula is known as the formula mass or the molecular mass.

A sample of an unknown substance contains 1.0 grams of copper and 0.558 gramsof chlorine, while a different sample of that same substance contains 2.0 grams of copper and 1.116 grams of chlorine. Which law does this observation demonstrate? the law of definite proportions the law of multiple proportions it demonstrates both of the above laws it does not demonstrate any law

the law of definite proportions That a particular substance has the same ratio of two elements by mass regardless of the sample size demonstrates the law of definite proportions, or the law of constant composition.

What law states that when two elements react to form more than one compound, a fixed mass of one element will react with masses of the other element in a ratio of small, whole numbers? the law of modern atomic theories the law of definite proportions the law of multiple proportions the law of conservation of mass

the law of multiple proportions The law of multiple proportions states that when two elements react to form more than one compound, a fixed mass of one element will react with masses of the other element in a ratio of small, whole numbers.

What unit of measurement pertains to the number of microscopic molecules in a sample? Great work! That's correct. the atomic number the molar mass the atomic mass unit the mole

the mole The mole is the unit of measurement that allows for the unit conversion between atomic mass units (amu) and grams (g). The ability to convert units allows for us to calculate macroscopic amounts of matter, while at the same time respecting the stoichiometric ratios of a reaction

The roman numeral in the chemical name represents the: the number of cations in the compound the number of anions in the compound the oxidation state of the anion the oxidation state of the cation

the oxidation state of the cation The roman numeral represents the oxidation state of the metal cation, or basically its formal charge.

Compare 1 mole of hydrogen with 1 mole of oxygen. They will have: Perfect. Your hard work is paying off 😀 the same number of atoms and the same masses. a different number of atoms and the same masses. the same number of atoms and different masses. a different number of atoms and different masses.

the same number of atoms and different masses. Consistent with its definition as an amount unit, 1 mole of any element contains the same number of atoms as 1 mole of any other element. However, the masses of 1 mole of different elements will differ since the masses of the individual atoms are drastically different.

Which of the following temperatures are equivalent to absolute zero (0 K)? Select all that apply. 74.93∘F −100∘C −273.15∘C −459.67∘F

−273.15∘C −459.67∘F We can convert from Kelvin to Celsius using the following equation: ∘C=K−273.15 Therefore, 0K−273.15=−273.15∘C We can convert from Celsius to Fahrenheit using the following equation: ∘F∘F=95×∘C+32=95×−273.15∘C+32=−459.67∘F Therefore, −273.15∘C and −459.67∘F show absolute zero on the Celsius and Fahrenheit scales.

What is 50 °F in Celsius?

10 To convert Fahrenheit into Celsius you need to use the equation: C=59(F−32) Plug in the numbers given and you get: C=59(50−32)=909=10

If we wish to convert a value in years into days, a conversion factor we could use would be: 1 year / 365 days 365 days / 1 year 1 year / 24 hours 24 hours / 1 year

365 days / 1 year

Absolute zero in Celsius is −273.15∘C. Convert this to degrees Fahrenheit.

459.67∘F

How many significant figures are in the number 10.004?

5 All of the digits in this number are significant, since zeroes that are trapped between non-zero digits are part of the measurement.

There are 4 gleeks in a glook, 7 glooks in a gluck, and 5 glucks in a glack. How many gleeks are in 4 glacks?

560 In order to solve this, we need to set up the following: 4 glacks×5 glucks1 glack×7 glooks1 gluck×4 gleeks1 glook=? Then, we need to cancel out appropriate units: 4 glacks×5 glucks1 glack×7 glooks1 gluck×4 gleeks1 glook4×5 glucks1×7 glooks1 gluck×4 gleeks1 glook4×51×7 glooks1×4 gleeks1 glook=?=?=? Finally, we multiply what remains to find the number of gleeks: 4×51×71×4 gleeks1=560 gleeks

Which of the following is true regarding significant figures? All zeros between significant digits are not significant. All zeros to the left of the decimal point are not significant. All nonzero digits are considered significant. All of the above.

All nonzero digits are considered significant.

Which word BEST completes the sentence below: _________ are any substance made up of matter and can be natural or man-made. A. atoms B. chemicals C. molecules D. elements

B. chemicals

Which is NOT a scientific field that is requires a knowledge of chemistry? A. physics B. sociology C. astronomy D. biology

B. sociology

Why is chemistry helpful in understanding how a toaster creates the brown color and crispy texture of toast? 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.

Chemistry is best defined as the study of which of the following? A. the properties of living organisms B. the electrical nature of matter C. the properties and history of the earth's physical structure and substance D. the properties and interactions of matter

D. the properties and interactions of matter

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

Matter is composed of only one type of atom.

Which of the following can be broken down into elements by chemical means?

a compound A compound can be broken down into two or more elements by chemical means. An element and atom are already in their most simple forms and cannot be broken down further. A mixture can be separated by physical changes rather than chemical.

Which of the following terms describes the smallest particle of a substance that still retains the chemical properties of that substance? Select all that apply

a molecule an atom Depending on whether the substance in question is an element or a compound, either an atom or a molecule is the smallest particle of that substance that retains its chemical properties. A substance cannot decompose into protons, neutrons and electrons without changing its very nature.

Which operation is performed to convert a temperature given in degrees Celsius to a temperature in kelvin?

add 273 𝑇K=𝑇°C+273.15TK=T°C+273.15 Kelvin and Celsius have a linear relationship, but not a proportional relationship. They do not have the same starting point, but they increase at the same rate. 0 K is absolute zero, which is about −273∘C, so to get Kelvin from Celsius, add 273.

Dimensional analysis can be used to compute:

all of the above imensional analysis can help us in a great number of every-day situations by simplifying seemingly complicated mathematical problems.

When adding numbers, the sum will have: as many decimal places as the number with fewest decimal places as many decimal places as the number with the most decimal places as many significant figures as the number with fewest significant figures as many significant figures as the number with the most significant figures

as many decimal places as the number with fewest decimal places 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.

Which of the following is NOT a unit used in the SI system? ampere atomic mass unit kilogram meter

atomic mass unit

If object A and object B have the same density, but object A has greater mass, then object A must have

greater volume 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.

accuracy

how close a measurement is to an accepted value

"The higher the pH of the water in a pond, the higher the algae growth." This statement is an example of a _____________. law theory fact hypothesis

hypothesis

A tentative explanation of observations that acts as a guide for gathering and checking information is called a: hypothesis law theory scientific method

hypothesis

Characterize the following statement: If you drink coffee before going to bed, it will take longer to fall asleep. observation hypothesis theory law

hypothesis

In some cases, volume can be found by cubing which of the following quantities? mass length time none of the above

length

The image below was captured over a hot mug of coffee on a cold morning. Which state(s) of matter are present in the image?

liquid gas The image shows steam condensing as it hits the cool air. Pure steam, which is in the gas phase, is invisible. The cloudy appearance comes from droplets of liquid water that form when the steam cools upon mixing with cold air.

You are using a digital balance that measures mass to the ten-thousandth of a gram, but it has been calibrated incorrectly. Measurements using this apparatus will produce: high accuracy but low precision low accuracy but high precision low accuracy and low precision high accuracy and high precision

low accuracy but high precision If it has been calibrated incorrectly, all the values will be off, and therefore inaccurate, but the mis-calibration will have the same effect on all values. They will all be off in the same direction and by roughly the same amount, so they will still be highly precise, meaning highly repeatable.

Which of the following is measured in grams or kilograms?

mass

Which of the following is NOT a base unit used in the SI system of measurement? A. second B. milliliter C. mole D. meter

milliliter

A scientist obtains a set of measurements that are very close to one another. These can be said to be: precise accurate identical none of the above

precise

A set of measurements that yield very similar results when repeated in the same manner are said to be: accurate precise both accurate and precise none of the above

precise

Measurements are said to be _____ if they yield very similar results when repeated in the same manner.

precise

In dimensional analysis, what is a conversion factor? accepted values for physical quantities theoretical quantities of matter experimental values for given quantities of matter ratios of physical quantities used to compare desired units

ratios of physical quantities used to compare desired units

The SI unit for time is the: second minute hour year

second

What physical state of matter is associated the particles having least amount of thermal energy?

solid

Units

standard of comparison for measurements

If you were on the moon, which has significantly less mass than the earth, your mass would:

stay the same Your mass does not change because of where you are in a gravitational field, it is an inherent characteristic of matte

Today, the meter is based on: a meter stick the height of a king a fraction of the distance from the equator to the north pole the distance light travels in a particular fraction of a second

the distance light travels in a particular fraction of a second

What is the standard SI unit of mass? the pound the meter the kilogram the gram

the kilogram

Volume

the measure of the amount of space occupied by an object.

True or false: the study of science has been organized into multiple fields, because it is too multifaceted to be studied as a whole.

true

When computing using dimensional analysis:

unit conversions can be done either simultaneously or separately 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.