Knewton Ch 1 & 2 Test Review

One 100 g sample comprised of molecule (A) is made up of 57.1 g of oxygen and 42.9 g of carbon. Another 100 g sample comprised of molecule (B) is made up of 72.7 g oxygen and 27.3 g carbon. How does the oxygen to carbon mass ratio for molecule A compare to the oxygen to carbon mass ratio for molecule B? Select the correct answer below: 1:2 1:3 3:4 2:2

1:2 57.1 g O / 42.9 g C = 1.22 g O per g C 72.7 g O / 27.3 g C = 2.66 g O per g C Ratio is 1:2

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

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

When 5.0 grams of calcium are burned in oxygen, 7.0 grams of calcium oxide result. What mass of oxygen reacted? Select the correct answer below: 1.0 grams 2.0 grams 5.0 grams 7.0 grams

2.0 grams The material gained 2.0 grams of mass which must have come from the oxygen.

If a 17.0 gram sample of ammonia contains 14.0 grams of nitrogen and 3.0 grams of hydrogen, what would a 8.5 gram sample of ammonia contain? Select the correct answer below: 7.0 grams nitrogen, 3.0 grams hydrogen 5.5 grams nitrogen, 3.0 grams hydrogen 4.25 grams nitrogen, 4.25 grams hydrogen 7.0 grams nitrogen, 1.5 grams hydrogen

7.0 grams nitrogen, 1.5 grams hydrogen The law of definite proportions tells us that the ratio of nitrogen to hydrogen must be constant, and 7.0 to 1.5 is the only answer that gives us the same ratio as the original sample.

Write the symbol for an atom with 34 protons and 44 neutrons. Include the mass number and the atomic number.

78/34Se It is given that the atom has 34 protons and 44 neutrons. The atomic number is equal to the number of protons, so the atomic number is 34, which corresponds to selenium (Se) on the periodic table. The mass number is equal to the total number of protons and neutrons in the nucleus, so the mass number is 34+44=78. The chemical symbol for a specific isotope of an element is written as AZX, where A is the mass number, Z is the atomic number, and X is the chemical symbol. Therefore, the chemical symbol for this isotope of selenium is Se3478.

What percentage of the atom is empty space? 5% 50% 90% 99.9%

99.9% As incredible as it sounds, the atom is almost entirely empty space, apart from the tiny nucleus at the center.

Which of the following is TRUE about heterogeneous mixtures? A heterogeneous mixture is a solution. A heterogeneous mixture can only be separated chemically. A heterogeneous mixture is not uniform in composition. A heterogeneous mixture is not a pure substance.

A heterogeneous mixture is not uniform in composition. A heterogeneous mixture is not a pure substance. Heterogeneous mixtures are not uniform in composition; this description only applies to homogeneous mixtures. Heterogeneous mixtures, like homogeneous mixtures, are also not pure substances. Since heterogeneous mixtures are not uniform in composition, they are not considered solutions.

There are two classifications for mixtures. Which of the following is one of those classifications? Select the correct answer below: A binary mixture A homogeneous mixture A normative mixture none of the above

A homogeneous mixture Of the choices listed, a homogeneous mixture is one of the two classes of mixtures. The second is a heterogeneous mixture.

Which sentence gives the correct definition of a mixture? A mixture is two or more pure substances combined. A mixture is a discrete unit of two or more atoms bound together. A mixture is two or more elements combined in a fixed ratio that cannot change.

A mixture is two or more pure substances combined. Pure substances: compounds and elements, can be mixed in arbitrary ratios. The resulting material is called a "mixture."

What is the empirical formula for the molecule C6O2H6?

C3OH3

Octane's molecular formula is C8H18. What is its empirical formula?

C4H9 The empirical formula must feature the simplest whole-number ratio of the constituent elements. The simplest form of the carbon: hydrogen ratio, given as 8:18, is 4:9. Therefore, the empirical formula is C4H9.

Given the following reaction: 8CO+17H2→ _________+_________ . Which of the following are products that do not violate any of Dalton's postulates? Select the correct answer below: CH18+8H2O CH+HO CH10+H2O

C8H18+8H2O Because atoms cannot be created or destroyed, the same number of atoms should be present after a reaction. C8H18+8H2O contains the same number of atoms as the reactants.

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.

_______ properties depend on the amount of matter that is being measured. intensive extensive chemical physical

Extensive properties depend on the amount of matter that is being measured.

What is the most abundant element in the universe? Select the correct answer below: helium hydrogen carbon oxygen

Hydrogen makes up around 75% of the visible mass of the universe.

What's the plum pudding model?

In 1904, Thomson proposed the "plum pudding" model of the atom. In his comparison, the negative electrons were represented by the raisins in the pudding and the dough contained the positive charge.

Ionic Compounds

Ionic compounds typically contain a metal cation. Ex: LiOH, FrI, CaC2

What element makes up most of the Earth's core?

Iron (Fe) makes up about 88.8% of Earth's core by mass.

According to this chart, the majority of gold on Earth resides in the core. Why is gold mined from the crust instead of from the core? Select the correct answer below: The gold in the core is mixed with too many other metals and is not worth extracting, while gold found in the crust is pure. The high temperatures in the core ruin the quality of the gold found there. Although there is more gold in the core than in the crust, it is easier to determine where gold deposits will be found within the crust than within the core. It is not possible to dig or drill down to the core.

It is not possible to dig or drill down to the core. Earth's core is about 2890 km below the surface, far beyond our means of drilling or digging.

Who was the first person to show strong empirical evidence for the existence of atoms? Select the correct answer below: Democritus Albert Einstein John Dalton Aristotle

John Dalton

The law of multiple proportions was formulated by _________, who used data and findings from Joseph Proust. Select the correct answer below: John Dalton Neils Bohr Ernest Rutherford Charles Darwin

John Dalton The law of multiple proportions was formulated by John Dalton, who used data and findings from Joseph Proust.

What scientist is credited with conducting experiments that led to the law of definite proportions? Select the correct answer below: Neils Bohr Ernest Rutherford Charles Darwin Joseph Proust

Joseph Proust is credited with the formulation of the law of definite proportions.

Julia is observing a room filled with carbon dioxide molecules (CO2). She believes that if all the carbon and oxygen atoms were counted they would fit the 1:2 ratio of a single carbon dioxide molecule. She also believes the masses of these atoms will follow the same 1:2 ratio. Which law is Julia describing in her prediction? Select the correct answer below: Law of Definite Proportions Law of Multiple Proportions Law of Conservation of Mass Boyle's Law

Law of Definite Proportions The law of definite proportions states that all samples of a pure compound contain the same elements in the same proportion by mass.

Which of the following CANNOT be classified as a compound? carbon dioxide sodium chloride lithium sugar

Lithium is an element.

Ionic compounds are compounds composed of ions, charged particles that form when an atom (or group of atoms) gains or loses electrons. (A cation is a positively charged ion; an anion is a negatively charged ion.)

Metal + Nonmetal → ionic compound (usually) Metal + Polyatomic ion → ionic compound (usually)

Molecules of glucose (blood sugar) contain 6 carbon atoms, 12 hydrogen atoms, and 6 oxygen atoms. What are the molecular and empirical formulas of glucose? Select the correct answer below: Molecular formula, C6H12O6; empirical formula, CH2O Molecular formula, C6H12O6; empirical formula, C6H12O6 Molecular formula, C2H4O; empirical formula, C8H16O4 Molecular formula, C2H4O; empirical formula, C2H4O

Molecular formula, C6H12O6; empirical formula, CH2O The molecular formula is C6H12O6: one molecule actually contains 6 carbon atoms, 12 hydrogen atoms, and 6 oxygen atoms. The simplest whole-number ratio of C to H to O atoms in glucose is 1:2:1, so the empirical formula is CH2O.

Which of the following statements is true about the relationship between atoms and molecules? Molecules are smaller than atoms. Molecules are made of two or more atoms that are bonded together. Molecules may consist of one type of atom, or multiple types of atoms. Pure elements are always composed of atoms and compounds are always composed of molecules.

Molecules are made of two or more atoms that are bonded together. Molecules may consist of one type of atom, or multiple types of atoms. Atoms are smaller units than molecules, since two or more atoms make a molecule. These chemically bonded atoms may be the same type (from the same element) or different types (different elements). Several pure elements exist in diatomic form, which is a molecule consisting of 2 atoms of the same element (for example, fluorine, or F2).

Which of the following is NOT an ionic compound? NaClO NO Li2O BeF2

NO Ionic compounds are generally composed of metals and nonmetals. NO contains nitrogen and oxygen, two nonmetallic elements, so NO is likely a molecular compound, not an ionic compound.

Which of the following compounds is considered a molecular compound? Select the correct answer below: NO2 Na3PO4 NaBr CaSO4

NO2 Molecular compounds are generally composed of nonmetallic elements. NO2 consists of only the nonmetallic elements nitrogen and oxygen. Therefore, NO2 is a molecular compound.

Which of the following is NOT a covalent compound? CO2 Na2O H2O NH3

Na2O Sodium is a metal and oxygen is a nonmetal, so this will be an ionic compound.

Covalent or molecular compounds form when elements share electrons in a covalent bond to form molecules. Molecular compounds are electrically neutral.

Nonmetal + Nonmetal → covalent compound (usually) Hydrogen + Nonmetal → covalent compound (usually)

Whose experiment measured the charge of the electron, allowing the mass of the electron to also be determined when combined with earlier results on the charge to mass ratio of the electron? Select the correct answer below: J.J. Thomson John Dalton Ernest Rutherford Robert Millikan

Robert Millikan Robert Millikan discovered the charge of the electron in his oil drop experiment. Using the existing charge-to-mass ratio for the electron, he was able to then calculate the mass of the electron.

What model for the atom was proposed by Hantaro Nagaoka? Select the correct answer below: plum pudding model solar system model nuclear model Saturn-like model

Saturn-like model Nagaoka imagined the atom as a sphere of positive charges surrounded by a ring-like halo of electrons, strongly resembling the planet Saturn.

Which of the following was Robert A. Millikan able to determine, either from his own work, or by building on the work of J. J. Thomson? Select all that apply. Select all that apply: The existence of an electron The charge of an electron. The mass of an electron The model of an atom with a small, positively charged nucleus.

The charge of an electron. The mass of an electron. Millikan was able to measure the charge of individual electrons, and was also able to determine the mass by combining his result with Thomson's measurement of the charge to mass ratio of the electron.

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

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 NOsub2.

Which of the following did J.J. Thomson determine as a result of his cathode ray experiments? Select the correct answer below: The existence of a small (lighter than an atom), negatively charged fundamental particle called the electron. The charge of an electron. The mass of the electron. The model of an atom consisting of a small, positively charged nucleus.

The existence of a small (lighter than an atom), negatively charged fundamental particle called the electron. J.J. Thomson's work led to the discovery of the electron.

The fundamental charge discovered by Millikan has a specific value of: Select the correct answer below: 3.2×10−18 C 1.6×10−18 C 1.6×10−19 C 4.8×10−19 C

The fundamental charge, discovered by Millikan, has a specific value of 1.6×10^−19 C.

Phases of matter are also referred to as: types states varieties positions

The phases of matter are also known as states of matter.

Which of the following statements is true about the two isotopes of carbon 13/6C and 12/6C? Select the correct answer below: They have different numbers of protons. They have different numbers of electrons. They have different numbers of neutrons. They have different chemical properties.

They have different numbers of neutrons. Isotopes are atoms of the same element with the same chemical properties that have different numbers of neutrons; 13/6C has seven neutrons and 12/6C has six neutrons.

A strong magnet placed under a piece of paper makes a three-dimensional pattern in iron filings that are placed on top of the paper. This is an example of which of the following? Select the correct answer below: a change in an extensive property a change in an intensive property a chemical change a physical change

a physical change A physical change is a change in the state or properties of matter without any accompanying change in chemical composition. In the organization of the filings into a three-dimensional form by the magnet, there is no chemical change. Also, none of the extensive or intensive properties of the magnet or filings change.

Dalton's theory views a chemical change as: Select the correct answer below: a loss of mass a gain of mass a rearrangement of atoms a transformation of atoms of one element to atoms of another element.

a rearrangement of atoms Dalton realized that a chemical change simply involves the rearrangement of atoms to form new combinations, or new compounds, and that atoms themselves do not change in such a process.

Every element on the periodic table has isotopes that contain: protons neutrons electrons all of the above

all of the above All elements contain all of these particles, which is why it is so important to understand them. Although one of hydrogen's isotopes does not have a neutron, hydrogen does have other neutron-containing isotopes.

Molecules with similar properties might have the same: Select the correct answer below: structural formula molecular formula empirical formula all of the above

all of the above All of these possibilities could lead to molecules having similar properties.

Modern atomic theory was formed due to the work of which of the following? Select the correct answer below: Ernest Rutherford J.J. Thomson Robert A. Millikan all of the above

all of the above Ernest Rutherford, J.J. Thomson, and Robert A. Millikan are all credited with contributing to modern atomic theory with regard to the discovery of the subatomic particle, the electron.

Dalton's atomic theory served to explain: Select the correct answer below: the law of conservation of matter the law of definite proportions the law of multiple proportions all of the above

all of the above It was the ability of Dalton's theory to explain all of the above observations that made it so powerful in changing the landscape of chemistry in the early 19th century.

Which of the following changes when the size of the sample changes? Select the correct answer below: an extensive property a electrical property an intensive property none of the above

an extensive property An extensive property changes when the size of a sample changes.

What did Ernest Rutherford's work uncover? Select the correct answer below: the existence of an electron the fundamental charge the mass of an electron an improved model of the atom

an improved model of the atom Rutherford's work helped improve the model of the atom. He discovered that atoms consist of a small charged nucleus surrounded by tiny electrons, and are mostly empty space.

Which of the following does not change if the sample size changes? Select the correct answer below: an extensive property a electrical property an intensive property none of the above

an intensive property An intensive property does not change if the sample size changes.

The temperature of an object is independent of the size of the sample. In other words, temperature is: Select the correct answer below: an intensive property an extensive property a fundamental constant of nature none of the above

an intensive property An intensive property is one which does not depend on the size of the sample, while an extensive property is one that does. For example, if two identical samples of the same water, each at 55∘C, were combined into one sample, the volume and mass would be double that of either of the original samples, but the temperature would still be 55∘C, so temperature is an example of an intensive property.

When depicting a molecule using the structural formula, the lines represent: Select the correct answer below: atoms bonds polarity none of the above

bonds The lines in a structural formula represent the covalent bonds in a molecule.

A(n) ________ change occurs as a result of a chemical reaction. Select the correct answer below: electrical chemical physical kinetic

chemical A chemical change occurs as a result of a chemical reaction.

Which of the following are considered intensive properties? Select all that apply. color volume density mass

color density Extensive properties depend upon the amount of matter in the sample; intensive properties do not. Color and density are intensive properties - mass and volume are not.

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

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.

What type of bond is characteristic of a molecular compound? Select the correct answer below: metallic bonds ionic bonds covalent bonds hydrogen bonds

covalent bonds Covalent bonds are found in molecular compounds.

All of the following are examples of chemical changes EXCEPT: Select the correct answer below: cracking an egg rusting of metal burning wood digesting a steak

cracking an egg

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

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

Suppose you have a drop of boiling water and a pot of boiling water. Even though the temperature is the same, the ramifications of spilling a drop versus dumping the whole pot on your skin are different.Heat is an example of an __________ property and temperature is an example of an __________ property. Select the correct answer below: intensive/extensive extensive/intensive extensive/extensive intensive/intensive

extensive/intensive An intensive property is a property that does not depend on the amount of matter present. The temperature of the boiling drop and the temperature of the boiling water in the pot are the same; temperature does not depend on amount, so it is an intensive property. If dropped on your skin, a drop of boiling water would cause only minimal pain, while a pot of boiling water would cause burns or blisters. Thus, the heat transferred to the skin depends on the amount of boiling water, so it is an extensive property.

A heterogeneous mixture like sand and water can be separated by: Select the correct answer below: cooling the vessel electrolysis shaking vigorously filtration

filtration Simply running the sand and water through a filter will keep the sand particles on one side while allowing the water to pass through, effectively separating the mixture.

Which is NOT a physical property? Select the correct answer below: density color melting point flammability

flammability Flammability is a chemical property, a property of a substance relating to its chemical reactivity.

Which of the following is an example of a chemical property? Select all that apply: flammability toxicity acidity density

flammability toxicity acidity The change of one type of matter into another type (or the inability to change) is a chemical property. Examples of chemical properties include flammability, toxicity, acidity, reactivity (many types), and heat of combustion.

Oil and water is an example of a: homogeneous mixture heterogeneous mixture pure substance compound

heterogeneous mixture Oil and water are separate compounds, so pure substance and compound are incorrect. 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: homogeneous mixture heterogeneous mixture pure substance compound

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

Mixtures can be classified as homogenous or __________ disingenuous disordered heterogenous separated

heterogenous Mixtures can be classified as homogenous or heterogenous.

Chocolate chip cookies are a __________ mixture. chemical means homogenous heternormative heterogenous

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

A mixture that contains a variety of visible components is known as a: homogenous mixture heterogenous mixture uniform mixture none of the above

heterogenous mixture A mixture that is comprised of various separate parts is known as a heterogenous mixture.

Clean swimming pool water is an example of a: homogeneous mixture heterogeneous mixture pure substance compound

homogeneous mixture In a swimming pool, there are other components beyond water - such as chlorine - and all of them are distributed evenly.

The portion of Earth's crust represented by the oceans and seas is called the __________. Select the correct answer below: outer crust hydrosphere lithosphere inner crust

hydrosphere The hydrosphere is the part of the crust containing water (the prefix hydro- means "water)".

When a change in a physical property is observed, Select the correct answer below: it could be because of a physical change. it must be because of a chemical change. it must be because of a chemical change and a physical change. it could be caused by a change that is considered both physical and chemical.

it could be because of a physical change. An observed change to a physical property like phase, hardness, or density could be caused by a physical change like a phase transition or a heating. It cannot be both because a physical change is one that does not include any accompanying change in its chemical composition.

All of the following are intensive properties EXCEPT: Select the correct answer below: melting point density length color

length Melting point, density, and color are intensive properties that are not dependent on the amount of matter present.

An atomic nucleus has a mass that is: Select the correct answer below: equal to the sum of the masses of its protons and neutrons. greater than the sum of the masses of its protons and neutrons. less than the sum of the masses of its protons and neutrons. not possible to calculate.

less than the sum of the masses of its protons and neutrons. The mass of an atomic nucleus will always be less than the sum of the masses of the protons and neutrons contained within it, by a quantity known as the mass defect.

J.J. Thomson's discovery of the electron relied on the observation that: Select the correct answer below: like charges repel and unlike charges attract like charges attract and unlike charges repel like charges and unlike charges repel like charges and unlike charges attract

like charges repel and unlike charges attract J.J. Thomson's work relied on the observation that like charges repel and opposite charges attract.

Which of the following is an example of a homogeneous mixture? oil and vinegar salad dressing chocolate chip cookie soil maple syrup

maple syrup

Which of the following is an extensive property? Select the correct answer below: malleability ductility mass density

mass An extensive property is a property that depends on the total amount of substance present. The mass is an extensive property because it is dependent on the amount of substance present, whereas malleability, ductility, and density are not.

The observation that an atom has slightly less mass than the sum of the masses of its subatomic particles is called which of the following? Select the correct answer below: mass defect mass discrepancy law of conservation of matter law of conservation of energy

mass defect This observation, although it follows the conservation of energy, defies the conservation of matter, and is called the mass defect. For example, the nucleus of a helium atom is composed of two neutrons and two protons. The sum of the masses of two neutrons and two protons is 4.03298 amu, while the actual mass of a helium nucleus is found to be only 4.00260 amu. The difference (in this case, 0.03038 amu) is the mass defect for helium. The energy corresponding to the mass defect, using the equation E=mc2, is referred to as the nuclear binding energy.

Atoms of the same element can have different: Select the correct answer below: atomic numbers mass numbers numbers of protons none of the above

mass numbers 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 is an intensive property? volume melting point weight heat

melting point Recall that an intensive property is a property of matter that is independent of the amount of substance in a sample. The melting point of a substance is an intensive property because it does not depend on the amount of substance present. Heat, volume, and weight are extensive properties because they depend on the amount of substance in a sample.

A __________ contains more than one type of element or compound. mixture pure substance compound element

mixture A mixture contains more than one type of element or compound. It is a material made up of two or more different substances which are mixed. A mixture refers to the physical combination of two or more substances in which identities are retained and are mixed in the form of solutions, suspensions or colloids.

The characteristics of atoms are responsible for the following aspects of a type of matter, EXCEPT: Select the correct answer below: color density monetary value luster

monetary value Monetary value is a man-made concept.

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

neutron 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.

Despite the units frequently seen on laboratory scales, the most appropriate unit below for quantifying weight is _______. Select the correct answer below: 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.

What gas is most prevalent in Earth's atmosphere? Select the correct answer below: nitrogen oxygen carbon dioxide silicate

nitrogen Nitrogen makes up about 78.1% of the atmosphere by volume.

Rutherford concluded that the ______ must be at the center of each atom. Select the correct answer below: positron neutron electron nucleus

nucleus Rutherford concluded that the nucleus must be at the center of each atom.

All of the atoms in the same element have the same: Select the correct answer below: mass number mass unit number of neutrons number of protons

number of protons All atoms of the same element have the same number of protons.

Where are electrons located? Select the correct answer below: inside the nucleus outside the nucleus underneath the nucleus none of the above

outside the nucleus The electrons have a negative charge, are located outside and orbit around the nucleus.

What is the origin of the oxygen gas that makes up about 21% of the atmosphere? Select the correct answer below: nuclear decay outgassing from Earth's rock layers meteorite impacts photosynthesis

photosynthesis Earth's atmosphere used to have a much lower oxygen concentration before the evolution of photosynthesis, which uses sunlight to convert water and carbon dioxide into sugar and oxygen.

Alpha particles have: Select the correct answer below: positive charge negative charge no mass none of the above

positive charge Because alpha particles have a positive charge, Rutherford was able to gain the insights he did in his gold foil experiments.

According to Thomson, electrons are attracted to ____________ charges and are repelled by ______ charges. negative, positive positive, negative positive, neutral neutral, negative

positive, negative According to Thomson, electrons are attracted to positive charges and are repelled by negative charges.

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

salad dressing Salad dressing is an example of a heterogenous mixture.

Which of the following is not considered a pure substance? water gold silver soil

soil

A homogeneous mixture is also called a: pure substance compound solution liquid

solution We will often refer to homogeneous mixtures, especially in liquid form, as solutions. A homogeneous mixture doesn't necessarily have to be a liquid, and mixtures can't be pure substances such as a single compound.

Which of the following is a mixture? a bar of gold sugar water helium carbon dioxide

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

Which of the following is a homogeneous mixture? tea trail mix an ice cream sundae a bowl of milk and cereal

tea In a homogeneous mixture the molecules of substances that make up the mixture are evenly distributed. Tea consists mainly of water, with additional compounds extracted from the tea leaves, and which are evenly distributed throughout the cup. Conversely, the ingredients in trail mix, a bowl of cereal, and an ice cream sundae are not distributed evenly and can be distinguished from one another.

Which of the following layers of Earth is the densest? Select the correct answer below: the inner core the outer core the mantle the crust

the inner core The core is dense because it is made of materials that are naturally denser (mostly iron) than the other layers, and because of the extremely high pressures. The inner core is even denser than the outer core because of the increased pressure.

What law states that a compound is always composed of the same elements in fixed proportions by mass? 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 definite proportions The law of definite proportions states that a compound is always composed of the same elements in fixed proportions by mass.

A sample of an unknown substance contains 24.0 grams of carbon and 2.0 grams of hydrogen. A sample of another unknown substance contains 24.0 grams of carbon and 6.0 grams of hydrogen. Which law does this observation demonstrate? Select the correct answer below: 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 multiple proportions That a fixed mass of carbon can react with a particular mass of hydrogen or precisely triple that mass of hydrogen demonstrates the law of multiple proportions.

Homogeneous mixtures may be in any phase EXCEPT: gas liquid solid they may be in any phase

they may be in any phase 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.

What does 3CO2 mean? Select the correct answer below: three carbon atoms and two oxygen atoms three carbon dioxide molecules three carbon atoms and one oxygen molecule three carbon atoms and two oxygen molecules

three carbon dioxide molecules The molecule is CO2, and the 3 means that there are three of these molecules.

A solution has a _______ composition. non-uniform varied uniform separated

uniform A solution is a type of homogeneous mixture that has a uniform composition.

Which is an extensive property? Select the correct answer below: volume density melting point viscosity

volume The volume of a substance depends on how much of it is present. The rest do not.

Which of the following is the correct relationship between weight and mass? Select the correct answer below: weight=mass/gravity mass=weight×gravity weight=mass×gravity gravity=mass/weight

weight=mass×gravity