Chemistry Final Exam- Ch 8-19 bb answers

Which coefficients correctly balance the formula equation CaO + H2O ® Ca(OH)2?

1,1,1

What is the maximum possible amount of product obtained in a chemical reaction? a. theoretical yield b. mole ratio c. actual yield d. percentage yield

A

In an equation, the symbol for a substance in water solution is followed by

AQ

Which equation is not balanced? a. 4H2 + 2O2 ® 4H2O b. H2 + H2 + O2 ® H2O + H2O c. 2H2 + O2 ® H2O d. 2H2 + O2 ® 2H2O

C

Which reactant controls the amount of product formed in a chemical reaction? a. mole ratio b. composition reactant c. limiting reactant d. excess reactant

C

Predict what happens when zinc is added to water. a. Zinc oxide forms. b. Steam is produced. c. Hydrogen is released. d. No reaction occurs.

D

The coefficients in a chemical equation represent the Selected Answer: Correctd. relative numbers of moles of reactants and products. Answers: a. masses, in grams, of all reactants and products. b. number of valence electrons involved in the reaction. c. number of atoms in each compound in a reaction. Correctd. relative numbers of moles of reactants and products.

D

Which of the following would be investigated in reaction stoichiometry? a. the masses of hydrogen and oxygen in water b. the types of bonds that break and form when acids react with metals c. the amount of energy released in chemical reactions d. the mass of potassium required to produce a known mass of potassium chloride

D

The equation AX ® A + X is the general equation for a

DECOMPOSITION REACTION

The reaction represented by the equation 2KClO3(s) ® 2KCl(s) + 3O2(g) is a(n)

DECOMPOSITION REACTION

The decomposition of a substance by an electric current is called

ELECTROLYSIS

Group 1 metals react with water to produce metal hydroxides and

HYDROCHLORIC ACID

The formulas for the products of the reaction between sodium hydroxide and sulfuric acid are

Na2SO4 and H2O

What happens to the volume of a gas during compression? Selected Answer: Correcta. The volume decreases. Answers: Correcta. The volume decreases. b. The volume remains constant. c. It is impossible to tell because all gases are different. d. The volume increases.

a

1 out of 1 points Correct Which is an example of gas diffusion? Selected Answer: Correctb. the odor of perfume spreading throughout a room Answers: a. inflating a flat tire Correctb. the odor of perfume spreading throughout a room c. a cylinder of oxygen stored under high pressure d. All of the above

b

The compressibility of a liquid is generally Selected Answer: Correctb. less than that of a gas. Answers: a. more than that of a gas. Correctb. less than that of a gas. c. zero. d. equal to that of a gas.

b

The intermolecular forces between particles in a liquid can involve all of the following except Selected Answer: Correctc. gravitational forces. Answers: a. hydrogen bonding. b. dipole-dipole attractions. Correctc. gravitational forces. d. London dispersion forces.

c

What determines the average kinetic energy of the molecules of any gas? Selected Answer: Correctc. temperature Answers: a. molar mass b. container volume Correctc. temperature d. pressure

c

Oxides of active metals, such as CaO, react with water to produce

metal hydroxides.

When sodium chlorate, NaClO3, decomposes, the products are

sodium chloride and oxygen.

A solid forms when the average energy of a substance's particles Selected Answer: Correcta. decreases. Answers: Correcta. decreases. b. decreases then increases. c. creates a random arrangement. d. increases.

a

If a gas with an odor is released in a room, it quickly can be detected across the room because it Selected Answer: Correcta. diffuses. Answers: Correcta. diffuses. b. condenses. c. is dense. d. is compressed.

a

The kinetic-molecular theory explains the behavior of Selected Answer: Correcta. solids, liquids, and gases. Answers: Correcta. solids, liquids, and gases. b. liquids and gases only. c. gases only. d. solids and liquids only.

a

Under which conditions do real gases most resemble ideal gases? Selected Answer: Correcta. low pressure and high temperature Answers: Correcta. low pressure and high temperature b. high pressure and low temperature c. low pressure and low temperature d. high pressure and high temperature

a

The density of a substance undergoes the greatest change when the substance changes from a Selected Answer: Correctb. liquid to a gas. Answers: a. solid to a liquid. Correctb. liquid to a gas. c. liquid to a solid. d. a molecular solid to an ionic solid.

b

When the formula equation mc012-1.jpg is correctly balanced the coefficient of Fe is number a. 7. b. 9. c. 2. d. 3.

b

According to the kinetic-molecular theory, particles of matter are in motion in Selected Answer: Correctc. solids, liquids, and gases. Answers: a. gases and liquids only. b. gases only. Correctc. solids, liquids, and gases. d. solids only.

c

An ideal gas is a hypothetical gas Selected Answer: Correctc. that conforms to all of the assumptions of the kinetic theory. Answers: a. not made of particles. b. made of motionless particles. Correctc. that conforms to all of the assumptions of the kinetic theory. d. whose particles have zero mass.

c

By which process do gases take the shape of their container? Selected Answer: Correctc. expansion Answers: a. diffusion b. evaporation Correctc. expansion d. adhesion

c

Diffusion between two gases occurs most rapidly if the gases are at Selected Answer: Correctc. high temperature and the molecules are small. Answers: a. high temperature and the molecules are large. b. low temperature and the molecules are small. Correctc. high temperature and the molecules are small. d. low temperature and the molecules are large.

c

The intermolecular forces between particles are Selected Answer: Correctc. stronger in liquids than in gases. Answers: a. stronger in gases than in solids. b. equal in strength in gases and in liquids. Correctc. stronger in liquids than in gases. d. weaker in solids than in liquids.

c

Which of these best describes vaporization? Selected Answer: Correctc. Both (a) and (b) Answers: a. the process by which a liquid changes to a gas b. the process by which a solid changes to a gas Correctc. Both (a) and (b) d. Neither (a) nor (b)

c

Why does the air pressure inside the tires of a car increase when the car is driven? Selected Answer: Correctc. The air particles inside the tire increase their speed because their temperature rises. Answers: a. Some of the air has leaked out. b. The atmosphere compresses the tire. Correctc. The air particles inside the tire increase their speed because their temperature rises. d. The air particles collide with the tire after the car is in motion.

c

The kinetic-molecular theory explains the properties of solids, liquids, and gases in terms of the energy of the particles and Selected Answer: Correctd. the forces that act between the particles. Answers: a. the mass of the particles. b. diffusion. c. gravitational forces. Correctd. the forces that act between the particles.

d

Two gases with unequal molar masses are injected into opposite ends of a long tube at the same time and allowed to diffuse toward the center. They should begin to mix Selected Answer: Correctd. closer to the end that holds the heavier gas. Answers: a. in approximately five minutes. b. closer to the end that holds the lighter gas. c. exactly in the middle. Correctd. closer to the end that holds the heavier gas.

d

Which best describes the particles of a liquid compared to those of a gas? Selected Answer: Correctd. less random Answers: a. higher in energy b. lower in density c. colder Correctd. less random

d

Which is an example of effusion? Selected Answer: Correctd. air slowly escaping from a pinhole in a tire Answers: a. helium dispersing into a room after a balloon pops b. oxygen and gasoline fumes mixing in an automobile carburetor c. the aroma of a cooling pie spreading across a room Correctd. air slowly escaping from a pinhole in a tire

d

Which substance has the lowest density? Selected Answer: Correctd. H2O(g) Answers: a. Hg(l) b. H2O(l) c. Hg(g) Correctd. H2O(g)

d

An element in the activity series can replace any element Selected Answer: a. below it on the list. b. in the periodic table. c. above it on the list. d. in its group.

A

For the reaction represented by the equation SO3 + H2O ® H2SO4, calculate the percentage yield if 500. g of sulfur trioxide react with excess water to produce 575 g of sulfuric acid. a. 93.9% b. 91.2% c. 82.7% d. 88.3%

A

If the percentage yield is equal to 100%, then a. the actual yield is equal to the theoretical yield. b. the actual yield is greater than the theoretical yield. c. there was no limiting reactant. d. the actual yield is less than the theoretical yield.

A

In most chemical reactions the amount of product obtained is a. less than the theoretical yield. b. equal to the theoretical yield. c. more than the percentage yield. d. more than the theoretical yield.

A

In the reaction represented by the equation 2Al2O3 ® 4Al + 3O2, what is the mole ratio of aluminum to oxygen? a. 4:3 b. 2:3 c. 10:6 d. 3:4

A

In the reaction represented by the equation N2 + 3H2 ® 2NH3, what is the mole ratio of hydrogen to ammonia? a. 3:2 b. 6:8 c. 1:1 d. 2:1

A

To determine the limiting reactant in a chemical reaction, one must know the Selected Answer: Correcta. available amount of each reactant. Answers: Correcta. available amount of each reactant. b. available amount of one of the reactants. c. speed of the reaction. d. amount of product formed.

A

Use the table below to answer the following questions. Element Symbol Atomic Mass Bromine Br 79.90 Calcium Ca 40.08 Carbon C 12.01 Chlorine Cl 35.45 Cobalt Co 58.93 Copper Cu 63.55 Fluorine F 19.00 Hydrogen H 1.01 Iodine I 126.90 Iron Fe 55.85 Lead Pb 207.2 Magnesium Mg 24.30 Mercury Hg 200.59 Nitrogen N 14.01 Oxygen O 16.00 Potassium K 39.10 Sodium Na 22.99 Sulfur S 32.01 For the reaction represented by the equation 2KClO3 ® 2KCl + 3O2, how many moles of potassium chlorate are required to produce 250. g of oxygen? a. 5.21 mol b. 2.00 mol c. 4.97 mol d. 4.32 mol

A

For the reaction represented by the equation Cl2 + 2KBr ® 2KCl + Br2, calculate the percentage yield if 200. g of chlorine react with excess potassium bromide to produce 410. g of bromine. a. 82.1% b. 73.4% c. 91.0% d. 98.9%

C

In most chemical reactions the amount of product obtained is Selected Answer: Correctc. less than the theoretical yield. Answers: a. more than the theoretical yield. b. more than the percentage yield. Correctc. less than the theoretical yield. d. equal to the theoretical yield.

C

In the reaction represented by the equation C + 2H2 ® CH4, what is the mole ratio of hydrogen to methane? Selected Answer: Correctc. 2:1 Answers: a. 2:4 b. 1:2 Correctc. 2:1 d. 1:1

C

In the reaction represented by the equation N2 + 3H2 ® 2NH3, what is the mole ratio of nitrogen to ammonia? a. 1:3 b. 2:3 c. 1:2 d. 1:1

C

In the word equation, sodium oxide + water ® sodium hydroxide, the formula for sodium hydroxide is represented by a. Na2OH. b. Na2O. c. NaOH. d. NaO2.

C

In writing a chemical equation that produces hydrogen gas, the correct representation of hydrogen gas is a. 2H. b. OH. c. H2. d. H.

C

Predict what happens when calcium metal is added to a solution of magnesium chloride. a. No reaction occurs. b. Gaseous calcium is produced. c. Calcium chloride forms. d. Magnesium calcite forms.

C

Predict what happens when nickel is added to a solution of potassium chloride. a. Potassium nickel chloride forms. b. Hydrochloric acid forms. c. No reaction occurs. d. Nickel chloride forms.

C

The activity series of metals indicates the ease with which metal a. nuclei fuse. b. atoms form covalent bonds. c. atoms lose electrons. d. atoms gain neutrons.

C

The reaction of calcium oxide, CaO, with water yields a. calcium and a salt. b. calcium and oxygen gas. c. calcium hydroxide. d. carbon dioxide and water.

C

The units of molar mass are a. amu/mol. b. mol/g. c. g/mol. d. amu/g.

C

What can be predicted by using an activity series? a. the amount of energy released by a chemical reaction b. the melting points of elements C. whether a certain chemical reaction will occur d. the electronegativity values of elements

C

What is the maximum possible amount of product obtained in a chemical reaction? Selected Answer: Correctc. theoretical yield Answers: a. mole ratio b. actual yield Correctc. theoretical yield d. percentage yield

C

What is the ratio of the actual yield to the theoretical yield, multiplied by 100%? a. Avogadro yield b. mole ratio c. percentage yield d. excess yield

C

Which reaction does not occur? Selected Answer: a. 2HCl(aq) + Mg(s) ® MgCl2(aq) + H2(g) b. Fe(s) + CuCl2(aq) ® FeCl2(aq) + Cu(s) c. 2HF(aq) + Cl2(g) ® F2(g) + 2HCl(aq) d. 2Na(s) + ZnF2(aq) ® 2NaF(aq) + Zn(s)

C

A chemical equation is balanced when the a. subscripts of the reactants equal the subscripts of the products. b. coefficients of the reactants equal the coefficients of the products. c. products and reactants are the same chemicals. d. same number of each kind of atom appears in the reactants and in the products.

D

A chemical equation is balanced when the a. products and reactants are the same chemicals. b. subscripts of the reactants equal the subscripts of the products. c. coefficients of the reactants equal the coefficients of the products. d. same number of each kind of atom appears in the reactants and in the products.

D

A chemist interested in the efficiency of a chemical reaction would calculate the a. mole ratio. b. energy released. c. rate of reaction. d. percentage yield.

D

For the reaction represented by the equation 2H2 + O2® 2H2O, how many moles of water can be produced from 6.0 mol of oxygen? a. 2.0 mol b. 18 mol c. 6.0 mol d. 12 mol

D

For the reaction represented by the equation AgNO3 + NaCl ® NaNO3 + AgCl, how many moles of silver chloride, AgCl, are produced from 7.0 mol of silver nitrate AgNO3? a. 2.3 mol b. 21 mol c. 1.0 mol d. 7.0 mol

D

Magnesium bromide (aq) + chlorine (g) yields a. Mg(s) and BrCl(aq). b. MgBrCl(aq). c. MgCl(aq) and Br2(l). d. MgCl2(aq) and Br2(l).

D

Predict what happens when lead is added to nitric acid. a. No reaction occurs. b. Oxygen is released. c. Lead oxide forms. d. Hydrogen is released.

D

The ability of an element to react is the element's a. valence. b. electronegativity. c. stability. d. activity.

D

To balance a chemical equation, it may be necessary to adjust the a. formulas of the products. b. number of products. c. subscripts. d. coefficients.

D

To balance a chemical equation, it may be necessary to adjust the a. number of products. b. formulas of the products. c. subscripts. d. coefficients.

D

What is the measured amount of a product obtained from a chemical reaction? a. theoretical yield b. percentage yield c. mole ratio d. actual yield

D

What is the small whole number that appears in front of a formula in a chemical equation? a. a superscript b. a subscript c. a ratio d. a coefficient

D

What is the study of the mass relationships of elements in compounds? a. Avogadro's principle b. percentage yield c. reaction stoichiometry d. composition stoichiometry

D

When the limiting reactant in a chemical reaction is completely used, the a. excess reactants begin combining. b. reaction slows down. c. reaction speeds up. d. reaction stops.

D

Which of the following is a formula equation for the formation of carbon dioxide from carbon and oxygen? a. CO2 ® C + O2 b. 2C + O ® CO2 c. Carbon plus oxygen yields carbon dioxide. d. C + O2 ® CO2

D

The equation A + X ® AX is the general equation for a(n)

SYNTHESIS REACTION

In a double-displacement reaction, hydrogen chloride and sodium hydroxide react to produce sodium chloride. Another product is

WATER

When a binary compound decomposes, what is produced?

2 ELEMENTS

Use the table below to answer the following questions. Element Symbol Atomic Mass Bromine Br 79.90 Calcium Ca 40.08 Carbon C 12.01 Chlorine Cl 35.45 Cobalt Co 58.93 Copper Cu 63.55 Fluorine F 19.00 Hydrogen H 1.01 Iodine I 126.90 Iron Fe 55.85 Lead Pb 207.2 Magnesium Mg 24.30 Mercury Hg 200.59 Nitrogen N 14.01 Oxygen O 16.00 Potassium K 39.10 Sodium Na 22.99 Sulfur S 32.01 For the reaction represented by the equation 2HNO3 + Mg(OH)2 ® Mg(NO3)2 + 2H2O, how many grams of magnesium nitrate are produced from 8.00 mol of nitric acid, HNO3, and an excess of Mg(OH)2? a. 818 g b. 593 g c. 148 g d. 445 g

B

Use the table below to answer the following questions. Element Symbol Atomic Mass Bromine Br 79.90 Calcium Ca 40.08 Carbon C 12.01 Chlorine Cl 35.45 Cobalt Co 58.93 Copper Cu 63.55 Fluorine F 19.00 Hydrogen H 1.01 Iodine I 126.90 Iron Fe 55.85 Lead Pb 207.2 Magnesium Mg 24.30 Mercury Hg 200.59 Nitrogen N 14.01 Oxygen O 16.00 Potassium K 39.10 Sodium Na 22.99 Sulfur S 32.01 For the reaction represented by the equation 2Na + Cl2 ® 2NaCl, how many grams of chlorine gas are required to react completely with 2.00 mol of sodium? a. 212.7 g b. 70.9 g c. 141.8 g d. 35.5 g

B

What is the name of a list of elements arranged according to the ease with which they undergo certain chemical reactions? a. reactivity list b. activity series c. reaction sequence d. periodic list

B

What is the study of the mass relationships among reactants and products in a chemical reaction? a. composition stoichiometry b. reaction stoichiometry c. electron configuration d. periodic law

B

When a solid produced by a chemical reaction separates from the solution it is called a. a molecule. b. a precipitate. c. a reactant. d. the mass of the product.

B

When the limiting reactant in a chemical reaction is completely used, the Selected Answer: Correctb. reaction stops. Answers: a. excess reactants begin combining. Correctb. reaction stops. c. reaction slows down. d. reaction speeds up.

B

Which coefficients correctly balance the formula mc004-1.jpg? a. 1,2,2 b. 1,1,2 c. 2,1,1 d. 2,2,2

B

Which equation is not balanced? a. mc001-3.jpg b. 2H2 + O2 ---> H2O c. mc001-2.jpg d. mc001-1.jpg

B

Use the table below to answer the following questions. Element Symbol Atomic Mass Bromine Br 79.90 Calcium Ca 40.08 Carbon C 12.01 Chlorine Cl 35.45 Cobalt Co 58.93 Copper Cu 63.55 Fluorine F 19.00 Hydrogen H 1.01 Iodine I 126.90 Iron Fe 55.85 Lead Pb 207.2 Magnesium Mg 24.30 Mercury Hg 200.59 Nitrogen N 14.01 Oxygen O 16.00 Potassium K 39.10 Sodium Na 22.99 Sulfur S 32.01 For the reaction represented by the equation Pb(NO3)2 + 2KI ® PbI2 + 2KNO3, how many moles of lead(II) iodide are produced from 300. g of potassium iodide and an excess of Pb(NO3)2? a. 0.904 mol b. 1.81 mol c. 11.0 mol d. 3.61 mol

A

Which coefficients correctly balance the formula mc010-1.jpg? a. 1,1,2 b. 2,1,1 c. 1,2,2 d. 2,2,2

A

Which observation does not indicate that a chemical reaction has occurred? a. change in total mass of substances b. evolution of heat and light c. formation of a precipitate d. production of a gas

A

Which of the following would be investigated in reaction stoichiometry? Selected Answer: Correcta. the mass of potassium required to produce a known mass of potassium chloride Answers: Correcta. the mass of potassium required to produce a known mass of potassium chloride b. the types of bonds that break and form when acids react with metals c. the amount of energy released in chemical reactions d. the masses of hydrogen and oxygen in water

A

Which reactant controls the amount of product formed in a chemical reaction? Selected Answer: Correcta. limiting reactant Answers: Correcta. limiting reactant b. composition reactant c. excess reactant d. mole ratio

A

According to the law of conservation of mass, the total mass of the reacting substances is a. always less than the total mass of the products. b. always equal to the total mass of the products. c. always more than the total mass of the products. d. sometimes more and sometimes less than the total mass of the products.

B

If a certain metal is placed in an ionic solution containing another metal and no reaction occurs, then the metal originally in the solution is Answers: a. unreactive. b. higher on the activity series. c. not on the activity series. d. a halogen.

B

In one type of synthesis reaction, an element combines with oxygen to yield a(n) a. metal. b. oxide. c. acid. d. hydroxide.

B

In the reaction represented by the equation N2 + 3H2 ® 2NH3, what is the mole ratio of hydrogen to ammonia? Selected Answer: Correctb. 3:2 Answers: a. 6:8 Correctb. 3:2 c. 1:1 d. 2:1

B

The equation AX + BY ® AY + BX is the general equation for a a. decomposition reaction. b. double-displacement reaction. c. synthesis reaction. d. single-displacement reaction.

B

The reaction represented by the equation Cl2(g) + 2KBr(aq) ® 2KCl(aq) + Br2(l) is a(n) a. synthesis reaction. b. single-displacement reaction. c. combustion reaction. d. decomposition reaction.

B

The reaction represented by the equation Mg(s) + 2HCl(aq) ® H2(g) + MgCl2(aq) is a a. double-displacement reaction. b. single-displacement reaction. c. decomposition reaction. d. composition reaction.

B