Deck 2: Chemistry

Question 1

Which of the following statements explains why elements of the alkali metal family are highly reactive?

A)Alkali metals are easily ionized.
B)Alkali metals are negatively charged.
C)Alkali metals have an odd number of protons.
D)Alkali metals have an odd number of electrons.

Answer 1

Alkali metals are easily ionized.

Question 2

Which of the following statements describes the role of a buffer?

A)It increases the rate of a reaction.
B)It keeps the pH of a solution within a small range.
C)It changes the oxidation states of elements in a compound.
D)It shifts the reaction equilibrium to favor more product formation.

Answer 2

It keeps the pH of a solution within a small range.

Question 3

How many grams of KCl are dissolved in 2.00 L of a 0.200 M solution of KCl?

A)0)400 g
B)14.9 g
C)29.8 g
D)400 g

Answer 3

29.8 g

Question 4

A leaf gently floats on a pond. Which of the following statements best explains why the leaf stays on top of the water?

A)The leaf has nonpolar covalent bonds between its atoms.
B)The density of the leaf is greater than the density of the water.
C)The water molecules are held tightly together by hydrogen bonding.
D)The hydrogen and oxygen atoms in the water are chemically bonded.

Question 5

Silver (Ag) has 47 protons in each atom. Based on this information, which of the following also describes an atom of silver

A)It has no neutrons.
B)It has 47 electrons.
C)It has 23 neutrons and 24 electrons.
D)It has a total of 94 neutrons and electrons.

Question 6

In a hydrogen fluoride (HF) molecule, a hydrogen atom and a fluorine atom are held together by a polar covalent bond. Which of the following best explains why this bond is polar?

A)the large difference in the atomic radii of hydrogen and fluorine atoms
B)the large difference in the atomic masses of hydrogen and fluorine atoms
C)the large difference in theelectronegativities of hydrogen and fluorine atoms
D)the large difference in the number of electrons of hydrogen andfluorine atoms

Question 7

Which of the following lists three states of water in order of increasing entropy?

A)ice, liquid, vapor
B)liquid, ice, vapor
C)ice, vapor, liquid
D)vapor, liquid, ice

Question 8

Which of the following activities could cause liquid molecules to overcome intermolecular attractive forces and become gas molecules?

A)adding a solute to the liquid
B)adding a catalyst to the liquid
C)increasing the temperature of the liquid
D)increasing the air pressure above the liquid

Question 9

Which of the following are most directly involved in chemical bonding?

A)protons
B)neutrons
C)alpha particles
D)valence electrons

Question 10

Which of the following statements explains why oxygen is classified asa pure substance and air is classifiedas a mixture?

A)Oxygen is more reactive than air.
B)Oxygen has a higher density than air.
C)Oxygen undergoes phase changes, whereas air is always a gas.
D)Oxygen contains only one substance, but air contains several substances.

Question 11

A hospital buys a compound that contains an isotope of barium. Several months later, most of the barium has changed to the element lanthanum. Which of the following is responsible for this change?

A)exposure to air
B)radioactive decay
C)reactions with the container wall
D)absorption of moisture from the air

Question 12

A student made a homogeneous mixture of water and salt. Which of the following statements applies to this homogeneous mixture?

A)This mixture is a solution.
B)This mixture is a pure substance.
C)The salt is not evenly distributed throughout this mixture.
D)The salt chemically combines with the water in this mixture.

Question 13

Which of the following statements best explains why elements in the same family of the periodic table have similar bonding properties?

A)The elements have similar atomic sizes.
B)The elements have similar atomic masses.
C)The elements have similar numbers of protons.
D)The elements have similar valence electron configurations.

Question 14

Which of the following statements best explains why potassium (K) reacts easily with bromine (Br)?

A)Potassium and bromine both have valence electrons in the fourth energy level.
B)Potassium and bromine have the same number of electrons in their highest energy levels.
C)Potassium has one electron in its highest energy level, and bromine needs one electron to complete its highest energy level.
D)Potassium needs one electron to complete its highest energy level, and bromine has an extra electron in its highest energy level.

Question 15

Which of the following statements best explains why atoms bond?

A)Atoms bond to make new substances.
B)Atoms bond to become less chemically stable.
C)Atoms bond to change from a liquid to a solid.
D)Atoms bond to become more chemically stable.

Question 16

When a sample of potassium chloride dissolves in water, it separates into potassium ions and chloride ions. Which of the following best accounts for the positive charge of the potassium ions?

A)They have extra mass.
B)They have a large volume.
C)They have fewer electrons than protons.
D)They have a high density of neutrons and protons.

Question 17

Which of the following statements applies to a nuclear fission reaction?

A)The reaction has no commercial applications.
B)The reaction takes place only at very high temperatures.
C)The reaction produces only shortlived radioactive waste.
D)The reaction releases large amounts of energy when nuclei split apart.

Question 18

Gold-198 has a half-life of approximately 3 days. If a 100 g sample of gold-198 decays for 9 days, approximately how much gold-198 remains in the sample?

A)13 g
B)25 g
C)33 g
D)50 g

Question 19

Formaldehyde in solution is used as a preservative. It has a melting point of -92°C. When the temperature of a sample of formaldehyde rises from -93°C to -91°C, which of the following occurs?

A)The molecules move more freely.
B)The molecules lose electrical charge.
C)The molecules break apart into atoms.
D)The molecules become fixed in a crystal structure.

Question 20

A hiker carries drinking water in a cloth-covered, metal container called a canteen. During the summer, the hiker wets the cloth covering so that the water in the canteen stays cool. Which of the following statements explains why a wet covering keeps the water cool?

A)A wet covering transfers coolness to the water in the canteen.
B)A wet covering insulates the canteen better than a dry covering.
C)Evaporation of water from the covering transfers heat away from the canteen.
D)Condensation of water from the covering transfers heat away from the canteen.

Question 21

Which of the following statements explains what happens to the gas inside a balloon as the external pressure on the balloon decreases and the temperature stays constant?

A)The volume increases.
B)The volume decreases.
C)The molecular speed increases.
D)The molecular speed decreases.

Question 22

Which of the following statements best explains why ice floats on water?

A)Water has a higher specific heat than ice.
B)Ice has the same molecular mass as water.
C)Heat is absorbed when water changes from the solid state to the liquid state
D)Hydrogen bonding causes water to be less dense in the solid state than in the liquid state.

Question 23

Which of the following did scientists learn about the atom from Rutherford's gold foil experiment?

A)Atoms combine in simple ratios to form compounds.
B)Electrons travel around the nucleus of an atom in concentric circular paths.
C)The mass of an atom and its positive charge are concentrated in the nucleus.
D)The atomic mass of an atom is equal to the number of protons and neutrons in the nucleus.

Question 24

Two elements in a molecule have the same electronegativity values. Which of the following most likely holds the elements together and why?

A)an ionic bond, because electrons transfer from one element to the other
B)a nonpolar covalent bond, because the elements share electrons equally
C)a polar covalent bond, because the elements do not share electrons equally
D)an intermolecular force, because the elements do not form a chemical bond

Question 25

Which of the following statements best explains why water vapor condenses as temperature decreases?

A)Collisions between water vapor molecules become elastic.
B)Water vapor molecules chemically react when they collide.
C)Water vapor molecules are pulled together by the force of gravity.
D)Attractive forces between water vapor molecules overcome molecular motion.

Question 26

Which of the following elements is a member of the halogen family and is located in period 3?

A)argon (Ar)
B)bromine (Br)
C)chlorine (Cl)
D)sulfur (S)

Question 27

Which of the following statements describes a difference between a mixture and a pure substance?

A)A mixture tends to be homogenous, while a pure substance tends to be heterogeneous.
B)A mixture has a specific melting point, while the melting point of a pure substance can vary.
C)The density of a mixture can change with temperature, but the density of a pure substance cannot change.
D)The composition of a mixture can vary from sample to sample, but the composition of a pure substance is always the same.

Question 28

Which of the following pieces of evidence best supports Bohr's idea that electrons occupy specific energy levels within an atom?

A)Sodium atoms become positive ions when they lose electrons.
B)Each element emits a unique brightline spectrum when it falls from an excited state to a ground state.
C)Beryllium atoms bombarded with alpha particles produce beams that are not influenced by magnetic fields.
D)Each element has physical and chemical properties that are unique to that element and different from those of other elements.

Question 29

Which of the following correctly pairs a phase of matter with its description?

A)Solid: Particles have no motion.
B)Liquid: Particles expand to fill any container in which they are placed.
C)Gas: Particles have higher amounts of energy than when in the liquid phase.
D)Liquid: Particles are more strongly attached to one another than when in the solid phase.

Question 30

Which of the following sections of the periodic table contains only metals?

A)group 2
B)group 18
C)period 2
D)period 6

Question 31

A person left a bottle of distilled water and a bottle of a sugary drink outside overnight. In the morning, one liquid was frozen but the other was not. Which liquid was frozen and why did it freeze?

A)The sugary drink froze because solutions are more dense than pure substances.
B)The distilled water froze because pure substances are more dense than solutions.
C)The sugary drink froze because solutions have a higher freezing point than pure substances.
D)The distilled water froze because pure substances have a higher freezing point than solutions.

Question 32

Which of the following characteristics of an element can be determined precisely by considering only the element's specificposition on the periodic table?

A)radius of each ion
B)density of the solid
C)boiling point of the liquid
D)number of protons in each atom

Question 33

The pH of four different solutions of common materials is measured. Which of the following lists the solutions in order from most acidic to most basic?

A)battery acid, lemon juice, blood, laundry detergent
B)lemon juice, battery acid, blood, laundry detergent
C)laundry detergent, blood, lemon juice, battery acid
D)battery acid, blood, laundry detergent, lemon juice

Question 34

Which of the following statements explains why the bond in hydrogen chloride (HCl) is polar covalent?

A)The atomic mass of chlorine is greater than that of hydrogen.
B)The electronegativity of chlorine is greater than that of hydrogen.
C)The diameter of a chlorine atom is greater than that of a hydrogen atom.
D)The number of valence electrons in a chlorine atom is greater than that in a hydrogen atom.

Question 35

Which of the following comparisons correctly describes subatomic particles?

A)An electron has a negative charge and a mass larger than the mass of a proton.
B)A neutron has a negative charge and a mass smaller than the mass of a proton.
C)A neutron has a neutral charge and a mass larger than the mass of an electron.
D)A proton has a positive charge and a mass smaller than the mass of an electron.

Question 36

One way that mixtures differ from pure substances is in the methods that can be used to separate them into their components.Which of the following is a method used to separate the components of some mixtures?

A)a nuclear reaction
B)a filtration process
C)a chemical reaction
D)an electrolysis process

Question 37

Which of the following describes the separation of the components of a mixture?

A)Water is broken down into hydrogen and oxygen.
B)Salt is isolated from seawater through evaporation.
C)Propane reacts with oxygen to form carbon dioxide and water.
D)Calcium carbonate decomposes to form calcium oxide and carbon dioxide.

Question 38

Which of the following statements accurately describes alpha particles in terms of charge and mass?

A)Alpha particles are positively charged and less massive than beta particles.
B)Alpha particles are negatively charged and less massive than beta particles.
C)Alpha particles are positively charged and more massive than beta particles.
D)Alpha particles are negatively charged and more massive than beta particles.

Question 39

A gas enters a compressor where it is converted to a liquid. Which of the following happens to the gas as it becomes a liquid?

A)It loses mass.
B)It releases heat.
C)It loses protons.
D)It releases electricity.

Question 40

Which of the following statements explains how a buffer maintains pH when small amounts of a strong base are added?

A)The salt in the buffer absorbs the base.
B)The water in the buffer dilutes the base.
C)The weak acid of the buffer neutralizes the base.
D)The weak base of the buffer neutralizes the base.

Question 41

Which of the following correctly describes molecules of two different gases if they are at the same temperature and pressure?

A)They must have the same mass.
B)They must have the same velocity.
C)They must have the same average kinetic energy.
D)They must have the same average potential energy.

Question 42

The density of a gas is 1.35 g/L at standard temperature and pressure (STP). What is the molar mass of the gas at STP?

A)0)0603 g/mol
B)6)02 g/mol
C)22.4 g/mol
D)30.2 g/mol

Question 43

Water cools from 2°C to -2°C. During this time, what happens to the motion of the molecules?

A)The motion of the molecules stops.
B)The motion of the molecules increases.
C)The motion of the molecules decreases.
D)The motion of the molecules remains the same.

Question 44

When stirred in 30°C water, 5 g of powdered potassium bromide, KBr, dissolves faster than 5 g of large crystals of potassium bromide. Which of the following best explains why the powdered KBr dissolves faster?

A)Powdered potassium bromide exposes more surface area to water molecules than large crystals of potassium bromide.
B)Potassium ions and bromide ions in the powder are smaller than potassium ions and bromide ions in the large crystals.
C)Fewer potassium ions and bromide ions have been separated from each other in the powder than in the crystals.
D)Powdered potassium bromide is less dense than large crystals of potassium bromide.

Question 45

Which of the following trends in the periodic table should be expected as the atomic number of the halogens increases from fluorine (F) to iodine (I)?

A)Atomic radius decreases.
B)Electronegativity decreases.
C)Atomic mass decreases.
D)Electron number decreases.

Question 46

Which of the following is an example of a chemical change?

A)burning a scented candle
B)cutting an apple into slices
C)freezing liquid water into an ice cube
D)melting a stick of butter to pour over popcorn

Question 47

The final elements produced by radioactive decay differ from the original radioactive elements because the nuclei of the ? nal elements are always

A)more stable.
B)increased in mass.
C)half as radioactive.
D)positively charged.

Question 48

Block X and Block Y have the same mass. Both blocks are placed into a container of pure water. Block X ? oats in the water, and Block Y sinks to the bottom of the container. Which of the following statements is an accurate conclusion from this demonstration?

A)Block Y is heavier than Block X.
B)Block Y is less dense than Block X.
C)Block Y has a smaller volume than Block X.
D)Block Y would ?oat if more water were added.

Question 49

Four different gases are all observed to have the same temperature. Which of the following conclusions is supported by this observation?

A)All four gases must have the same mass.
B)All four gases must have the same pressure.
C)All four gases must have equal numbers of particles.
D)All four gases must have equal average kinetic energies.

Question 50

Atoms of element A and atoms of element B react to form a compound. In the reaction, the radius of each atom of element A is decreased. Which of the following explains this decrease in atomic radius in the reaction?

A)The atoms of element A lose electrons to atoms of element B.
B)The atoms of element A gain neutrons from atoms of element B.
C)Nuclear particles are converted into energy in atoms of element A.
D)Protons become more densely packed in the nuclei of element A atoms.

Question 51

Which of the following correctly describes a trend from top to bottom in the group 2 (2A) elements on the periodic table?

A)Ionic radius decreases.
B)Ionic charge increases.
C)Atomic radius increases.
D)Atomic number decreases.

Question 52

Which of the following is the same for both hydrogen and potassium?

A)atomic mass
B)total mass of neutrons
C)number of valence electrons
D)number of ?lled energy levels

Question 53

Which of the following helps explain why honey dissolves more rapidly in hot water than in cold water?

A)The honey and hot water form more covalent bonds.
B)The hot water is more chemically reactive with the honey.
C)The honey breaks down into free atoms more quickly in the hot water.
D)The greater motion of hot water molecules disperses the honey more quicly.

Question 54

The addition of 500 J of energy to a block of iron causes a rise in the average kinetic energy of the atoms in the block. Which of the following instruments can best be used to observe this change?

A)a ruler
B)a balance
C)a thermometer
D)a graduated cylinder

Question 55

Which of the following is an example of nuclear fusion?

A)Hydrogen-1 and hydrogen-2 combine to form helium-3.
B)Polonium-210 decays into lead-206 and an alpha particle.
C)Carbon-14 breaks down into a beta particle and nitrogen-14.
D)Uranium-235 and a neutron produce barium-141, krypton-92, and three neutrons.

Question 56

Based on its position on the periodic table, which of the following elements is a nonmetal?

A)potassium (K)
B)vanadium (V)
C)nickel (Ni)
D)bromine (Br)

Question 57

As heat is slowly added to a glass of ice water, the temperature remains at 0°C. Which of the following statements explains why the temperature of the mixture of ice and water remains constant as heat is added?

A)Heat is stored in the solid ice.
B)Heat is stored in the liquid water.
C)Heat is used to turn the solid ice into liquid water.
D)Heat is absorbed equally by the solid ice and the liquid water.

Question 58

A leaf gently floats on a pond. Which of the following statements best explains why the leaf stays on top of the water?

A)The leaf has nonpolar covalent bonds between its atoms.
B)The density of the leaf is greater than the density of the water.
C)The water molecules are held tightly together by hydrogen bonding.
D)The hydrogen and oxygen atoms in the water are chemically bonded.

Question 59

In a hydrogen fluoride (HF) molecule, a hydrogen atom and a fluorine atom are held together by a polar covalent bond. Which of the following best explains why this bond is polar?

A)the large difference in the atomic radii of hydrogen and fluorine atoms
B)the large difference in the atomic masses of hydrogen and fluorine atoms
C)the large difference in theelectronegativities of hydrogen and fluorine atoms
D)the large difference in the number of electrons of hydrogen andfluorine atoms

Question 60

Which of the following occurs in an ionic bond?

A)Two ions share protons.
B)Two ions share electrons.
C)Similarly charged ions attract.
D)Oppositely charged ions attract.

Question 61

Which of the following observed properties is most reliable in classifying a substance as a metal?

A)good conductor of heat
B)low melting temperature
C)unreactive with other elements
D)crumbles when hit by a hammer

Question 62

Which of the following statements describes an exothermic reaction but not an endothermic reaction?

A)Energy is destroyed during the reaction.
B)Energy is used to form chemical bonds.
C)Energy is used to break chemical bonds.
D)Energy is released as heat during the reaction.

Question 63

Which of the following statements explains why oxygen is classified asa pure substance and air is classifiedas a mixture?

A)Oxygen is more reactive than air.
B)Oxygen has a higher density than air.
C)Oxygen undergoes phase changes, whereas air is always a gas.
D)Oxygen contains only one substance, but air contains several substances.

Question 64

The pH of milk is 6.4. Based on this information, which of the following statements best describes milk?

A)It is very basic.
B)It is very acidic.
C)It is slightly basic.
D)It is slightly acidic.

Question 65

A student made a homogeneous mixture of water and salt. Which of the following statements applies to this homogeneous mixture?

A)This mixture is a solution.
B)This mixture is a pure substance.
C)The salt is not evenly distributed throughout this mixture.
D)The salt chemically combines with the water in this mixture.

Question 66

Which of the following statements best explains why elements in the same family of the periodic table have similar bonding properties?

A)The elements have similar atomic sizes.
B)The elements have similar atomic masses.
C)The elements have similar numbers of protons.
D)The elements have similar valence electron configurations.

Question 67

Which of the following statements describes all exothermic reactions?

A)Exothermic reactions form gases.
B)Exothermic reactions require a catalyst.
C)The energy of the reactants is lower than the energy of the products.
D)The energy of the reactants is higher than the energy of the products.

Question 68

Which of the following statements best explains why potassium (K) reacts easily with bromine (Br)?

A)Potassium and bromine both have valence electrons in the fourth energy level.
B)Potassium and bromine have the same number of electrons in their highest energy levels.
C)Potassium has one electron in its highest energy level, and bromine needs one electron to complete its highest energy level.
D)Potassium needs one electron to complete its highest energy level, and bromine has an extra electron in its highest energy level.

Question 69

When a sample of potassium chloride dissolves in water, it separates into potassium ions and chloride ions. Which of the following best accounts for the positive charge of the potassium ions?

A)They have extra mass.
B)They have a large volume.
C)They have fewer electrons than protons.
D)They have a high density of neutrons and protons.

Question 70

Which of the following characteristics allows blood to resist changes in pH?

A)acidity
B)basicity
C)buffering capacity
D)clotting factors

Question 71

Which of the following statements applies to a nuclear fission reaction?

A)The reaction has no commercial applications.
B)The reaction takes place only at very high temperatures.
C)The reaction produces only shortlived radioactive waste.
D)The reaction releases large amounts of energy when nuclei split apart.

Question 72

Formaldehyde in solution is used as a preservative. It has a melting point of -92°C. When the temperature of a sample of formaldehyde rises from -93°C to -91°C, which of the following occurs?

A)The molecules move more freely.
B)The molecules lose electrical charge.
C)The molecules break apart into atoms.
D)The molecules become fixed in a crystal structure.

Question 73

Which of the following solutions has the highest concentration of solute?

A)1)0 mol solute in 200 mL solvent
B)2)0 mol solute in 500 mL solvent
C)3)0 mol solute in 1 L solvent
D)4)0 mol solute in 1.5 L solvent

Question 74

A hiker carries drinking water in a cloth-covered, metal container called a canteen. During the summer, the hiker wets the cloth covering so that the water in the canteen stays cool. Which of the following statements explains why a wet covering keeps the water cool?

A)A wet covering transfers coolness to the water in the canteen.
B)A wet covering insulates the canteen better than a dry covering.
C)Evaporation of water from the covering transfers heat away from the canteen.
D)Condensation of water from the covering transfers heat away from the canteen.

Question 75

Which of the following statements best explains why ice floats on water?

A)Water has a higher specific heat than ice.
B)Ice has the same molecular mass as water.
C)Heat is absorbed when water changes from the solid state to the liquid state
D)Hydrogen bonding causes water to be less dense in the solid state than in the liquid state.

Question 76

Which of the following did scientists learn about the atom from Rutherford's gold foil experiment?

A)Atoms combine in simple ratios to form compounds.
B)Electrons travel around the nucleus of an atom in concentric circular paths.
C)The mass of an atom and its positive charge are concentrated in the nucleus.
D)The atomic mass of an atom is equal to the number of protons and neutrons in the nucleus.

Question 77

Two elements in a molecule have the same electronegativity values. Which of the following most likely holds the elements together and why?

A)an ionic bond, because electrons transfer from one element to the other
B)a nonpolar covalent bond, because the elements share electrons equally
C)a polar covalent bond, because the elements do not share electrons equally
D)an intermolecular force, because the elements do not form a chemical bond

Question 78

Which of the following statements best explains why water vapor condenses as temperature decreases?

A)Collisions between water vapor molecules become elastic.
B)Water vapor molecules chemically react when they collide.
C)Water vapor molecules are pulled together by the force of gravity.
D)Attractive forces between water vapor molecules overcome molecular motion.

Question 79

Which of the following statements describes a difference between a mixture and a pure substance?

A)A mixture tends to be homogenous, while a pure substance tends to be heterogeneous.
B)A mixture has a specific melting point, while the melting point of a pure substance can vary.
C)The density of a mixture can change with temperature, but the density of a pure substance cannot change.
D)The composition of a mixture can vary from sample to sample, but the composition of a pure substance is always the same.

Question 80

Which of the following pieces of evidence best supports Bohr's idea that electrons occupy specific energy levels within an atom?

A)Sodium atoms become positive ions when they lose electrons.
B)Each element emits a unique brightline spectrum when it falls from an excited state to a ground state.
C)Beryllium atoms bombarded with alpha particles produce beams that are not influenced by magnetic fields.
D)Each element has physical and chemical properties that are unique to that element and different from those of other elements.