Chem 121 - Chapter 7

In this reaction, what is the coefficient for calcium oxide? CaO(s) + CO2(g) → CaCO3(s) A) 1 B) 2 C) 3 D) 4 E) 5

A) 1

3.00 moles of NO2 have a mass of A) 138 g. B) 46.0 g. C) 30.0 g. D) 90.0 g. E) 45.0 g.

A) 138 g.

How many grams of NO are required to produce 145 g of N2 in the following reaction? 4NH3(g) + 6NO(g) → 5N2(g) + 6H2O(l) A) 186 g B) 155 g C) 125 g D) 129 g E) 145 g

A) 186 g

Mg3N2(s) + 6H2O(l) → 3Mg (OH)2(s) + 2NH3(g) 58) What is the correct form of the conversion factor needed to convert the number of moles of H2O to the number of moles of NH3 produced? A) 2 moles of NH3/6 moles of H2O B) 6 moles of H2O/2 moles of NH3 C) 1 mole of Mg3N2/6 moles of H2O D) 18g of H2O/1 mole of H2O E) 18g of H2O/17g of NH3

A) 2 moles of NH3/6 moles of H2O

When 85.0 g of CH4 are mixed with 160. g of O2 what is the maximum amount of CO2 that can be produced? CH4 + 2O2 → CO2 + 2H2O A) 2.50 moles B) 5.00 moles C) 5.31 moles D) 7.81 moles

A) 2.50 moles

How many moles of iron are present in 3.15 × 1024 atoms of iron? A) 5.23 moles B) 1.90 moles C) 292 moles D) 0.523 moles E) 1.90 × 1048 moles

A) 5.23 moles

Calculate the molar mass of potassium chloride, KCl. A) 74.6 g B) 54.5 g C) 6.74 g D) 67.4 g E) 19.0 g

A) 74.6 g

The molar mass of C3H8O2 is A) 76.0 g. B) 60.0 g. C) 29.0 g. D) 69.0 g. E) 52.0 g.

A) 76.0 g.

How many grams of Fe2O3 are there in 0.500 mole of Fe2O3? A) 79.9 g B) 35.9 g C) 63.8 g D) 51.9 g E) 160. g

A) 79.9 g

What is oxidized and what is reduced in the following reaction? 2Al(s) + 3Br2(g) → 2AlBr3(s) A) Al is oxidized and Br2 is reduced. B) AlBr3 is reduced and Br2 is oxidized. C) Al is reduced and Br2 is oxidized. D) AlBr3 is reduced and Al is oxidized. E) AlBr3 is oxidized and Al is reduced.

A) Al is oxidized and Br2 is reduced.

Any reaction that absorbs 150 kcal of energy can be classified as A) endothermic. B) exothermic. C) activated. D) reduction. E) oxidation.

A) endothermic.

Avogadro's number is the number of A) particles in 1 mole of a substance. B) amu in 1 mole of a substance. C) grams in 1 mole of a substance. D) moles in 6.02 × 1023 grams of an element. E) moles in 6.02 × 1023 amu of an element.

A) particles in 1 mole of a substance.

Which of the following correctly gives the best coefficients for the reaction below? N2H4+ H2O2 → N2+ H2O A) 1, 1, 1 ,1 B) 1, 2, 1, 4 C) 2, 4, 2, 8 D) 1, 4, 1, 4 E) 2, 4, 2, 4

B) 1, 2, 1, 4

2Mg + O2 → 2MgO How many moles of magnesium are needed to react with 0.50 mole of O2? A) 0.50 mole B) 1.0 moles C) 2.0 moles D) 3.0 moles E) 4.0 moles

B) 1.0 moles

How many moles of carbon atoms are there in 0.500 mole of C2H6? A) 0.500 moles B) 1.00 moles C) 3.00 moles D) 6.02 × 1023 moles E) 4.00 moles

B) 1.00 moles

In the following reaction, when the equation is correctly balanced, what is the correct coefficient for sodium chloride? Pb(NO3)2(aq) + NaCl(aq) → PbCl2(s) + NaNO3(aq) A) 1 B) 2 C) 3 D) 4 E) 5

B) 2

In the following reaction, when the equation is correctly balanced, what is the correct coefficient for aluminum chloride? Al(s) + Cl2(g) → AlCl3(s) A) 1 B) 2 C) 3 D) 4 E) 5

B) 2

2Mg + O2 → 2MgO 53) The number of moles of oxygen gas needed to react with 4.0 moles of Mg is A) 1.0 mole. B) 2.0 moles. C) 3.0 moles. D) 4.0 moles. E) 6.0 moles.

B) 2.0 moles.

How many moles of water, H2O, are present in 75.0 g of H2O? A) 4.41 moles B) 4.16 moles C) 75.0 moles D) 7.50 moles E) 1.35 × 103 moles

B) 4.16 moles

How many grams of glucose (C6H12O6) are in 3.55 moles of glucose? A) 180. g B) 639 g C) 103 g D) 426 g E) 50.7 g

B) 639 g

Calculate the molar mass of magnesium chloride, MgCl2. A) 24.3 g B) 95.2 g C) 125.9 g D) 59.8 g E) 70.0 g

B) 95.2 g

When 3.05 moles of CH4 are mixed with 5.03 moles of O2 the limiting reactant is CH4 + 2O2 → CO2 + 2H2O A) CH4. B) O2. C) CO2. D) H2O.

B) O2.

When 85.0 g of CH4 are mixed with 160. g of O2 the limiting reactant is CH4 + 2O2 → CO2 + 2H2O A) CH4. B) O2. C) CO2. D) H2O.

B) O2.

The ________ is the minimum energy needed for a chemical reaction to begin. A) reaction energy B) activation energy C) energy of reactants D) energy of products E) heat of reaction

B) activation energy

What type of reaction is: CH4 + 2O2 → CO2 + 2H2O + 218 kcal? A) an endothermic reaction B) an exothermic reaction C) a single replacement reaction D) a combination reaction E) a decomposition reaction

B) an exothermic reaction

What is the classification for this reaction? SO3(g) + H2O (l) → H2SO4(l) A) decomposition B) combination C) replacement D) double replacement E) oxidation reduction

B) combination

In an endothermic reaction A) heat flows out of the system. B) energy is absorbed by the system. C) the temperature of the system increases. D) the products have less energy that the reactants. E) the products have the same energy that the reactants.

B) energy is absorbed by the system.

If the reaction shown below is exothermic, the energy level of the reactants is H2 + O2 → 2H2O A) lower than that of the products. B) higher than that of the products. C) the same as that of the products. D) possibly lower, possibly higher than that of the products. E) higher than the activation energy of the reaction.

B) higher than that of the products.

Which of the following describes an oxidation reaction? A) loss of electrons or loss of oxygen B) loss of electrons or gain of oxygen C) loss of electrons or gain of hydrogen D) gain of electrons or gain of oxygen E) gain of electrons or loss of H

B) loss of electrons or gain of oxygen

In an oxidation-reduction reaction, the substance oxidized always A) takes on oxygen atoms. B) shows a loss of electrons. C) gives up hydrogen atoms. D) shows a gain of electrons. E) becomes a charged species.

B) shows a loss of electrons.

In any balanced chemical equation, the number of each type of atom on both sides of the equation is A) doubled. B) the same. C) decreased by one. D) increased by one. E) dependent on the temperature.

B) the same.

How many grams of hydrogen are needed to produce 1.80 g of water according to this equation? 2H2 + O2 → 2H2O A) 0.100 g B) 0.180 g C) 0.200 g D) 2.00 g E) 4.00 g

C) 0.200 g

2Mg + O2 → 2MgO The number of moles of MgO produced when 0.20 mole of O2 reacts completely is A) 0.10 mole. B) 0.20 mole. C) 0.40 mole. D) 0.60 mole. E) 0.80 mole.

C) 0.40 mole.

Find the mass of AlCl3 that is produced when 10.0 grams of Al2O3 react with 10.0 g of HCl according to the following equation. Al2O3(s) + 6HCl(aq) → 2AlCl3(aq) + 3H2O(aq) A) 16.2 g B) 20.0 g C) 12.2 g D) 10.0 g E) 6.10 g

C) 12.2 g

What is the molar mass of sodium phosphate, Na3PO4? A) 119 g B) 308 g C) 164 g D) 226 g E) 354 g

C) 164 g

For the reaction: 2H2O(l) + 137 kcal → 2H2 (g) + O2 (g), how many kcal are needed to form 2.00 moles O2 (g)? A) 68.5 kcal B) 137 kcal C) 274 kcal D) 190. kcal E) 548 kcal

C) 274 kcal

In the following reaction, when the equation is correctly balanced, what is the correct coefficient for H2? Fe(s) + HCl(aq) → FeCl3(aq) + H2(g) A) 1 B) 2 C) 3 D) 4 E) 5

C) 3

What is the coefficient of hydrogen, H2, when the following equation is balanced? Al + H2SO4 → Al2(SO4)3+ ? H2 A) 1 B) 2 C) 3 D) 4 E) 5

C) 3

How many kcal are produced when 32.0 g of CH4 react? CH4 + 2O2 → CO2 + 2H2O + 218 kcal A) 218 kcal B) 109 kcal C) 436 kcal D) 6.81 kcal E) 698 kcal

C) 436 kcal

What is the coefficient for carbon dioxide in the balanced equation? C5H12 + ? O2 → ? CO2+ ? H2O A) 2 B) 4 C) 5 D) 6 E) 8

C) 5

In the reaction of nitrogen gas, N2, with hydrogen gas, H2, to form ammonia gas, NH3 , how many moles of hydrogen are needed to react with two moles of nitrogen? A) 2 moles B) 4 moles C) 6 moles D) 8 moles E) 10 moles

C) 6 moles

Find the mass of AlCl3 that is produced when 25.0 grams of Al2O3 react with excess HCl according to the following equation. Al2O3(s) + 6HCl(aq) → 2AlCl3(aq) + 3H2O(l) A) 155 g B) 72.9 g C) 65.4 g D) 32.6 g E) 16.3 g

C) 65.4 g

When 60.0 g of CH4 reacts with excess O2, the actual yield of CO2 is 112 g. What is the percent yield? CH4 + 2O2 → CO2 + 2H2O A) 53.6 % B) 187 % C) 67.9 % D) 46.4 %

C) 67.9 %

How many atoms of neon are present in 1.30 moles of neon? A) 3.15 × 10^23 atoms B) 4.63 × 10^23 atoms C) 7.83 × 10^23 atoms D) 6.02 × 10^23 atoms E) 7.83 × 10^24 atoms

C) 7.83 × 10^23 atoms

The molar mass of calcium hydroxide, Ca(OH)2, is A) 58.1 g. B) 57.1 g. C) 74.1 g. D) 114.2 g. E) 38.0 g.

C) 74.1 g.

In the reaction of silver nitrate with sodium chloride, how many grams of silver chloride will be produced from 100. g of silver nitrate when it is mixed with an excess of sodium chloride? The equation for the reaction is below. AgNO3(aq) + NaCl(aq) → AgCl(s) + NaNO3(aq) A) 107.9 g B) 169.9 g C) 84.4 g D) 0.589 g E) 58.9 g

C) 84.4 g

Which of the following is an oxidation-reduction reaction? A) CaCl2+ Na2SO4 → CaSO4+ 2NaCl B) KOH + HNO3 → H2O + KNO3 C) N2+ O2 → 2NO D) AgNO3+ NaCl → AgCl + NaNO3 E) Al2(SO4)3 + 6KOH → 2Al(OH)3+ 3K2SO4

C) N2+ O2 → 2NO

The reaction of carbon with oxygen to produce carbon monoxide is an example of which class of reaction? 2C(s) + O2(g) → 2CO(g) A) single replacement B) double replacement C) combination D) catalytic E) endothermic

C) combination

How many moles of K2SO4 are in 15.0 g of K2SO4? A) 0.172 moles B) 2.61 × 103 moles C) 0.111 moles D) 0.0861 moles E) 0.119 moles

D) 0.0861 moles

0.100 mole of lithium has a mass of A) 3.00 g. B) 0.300 g. C) 6.94 g. D) 0.694 g. E) 0.700 g.

D) 0.694 g.

60) How many grams of MgO are produced when 40.0 grams of O2 react completely with Mg? A) 30.4 g B) 50.4 g C) 60.8 g D) 101 g E) 201 g

D) 101 g

Mg3N2(s) + 6H2O(l) → 3Mg (OH)2(s) + 2NH3(g) When 36.0 g of H2O react, how many grams of NH3 are produced? A) 34.0 g B) 10.0 g C) 5.67 g D) 11.3 g E) 102 g

D) 11.3 g

What is the molar mass of copper(II) sulfate, CuSO4? A) 16.0 g B) 63.6 g C) 111.6 g D) 159.6 g E) 319.2 g

D) 159.6 g

For the reaction: 2H2O(l) + 137 kcal → 2H2 (g) + O2 (g), how many kcal are needed to react 50.0 g H2O(l)? A) 380. kcal B) 137 kcal C) 274 kcal D) 190. kcal E) 760. kcal

D) 190. kcal

How many molecules of water, H2O, are present in 75.0 g of H2O? A) 75.0 molecules B) 4.17 molecules C) 7.53 × 1024 molecules D) 2.51 × 1024 molecules E) 5.02 × 1024 molecules

D) 2.51 × 1024 molecules

One mole of neon atoms has a mass of A) 6.02 × 1023 grams. B) 14.0 g. C) 10.0 g. D) 20.2 g. E) 30.2 g.

D) 20.2 g.

How many grams of N2 are produced from 100. g of NH3 in the following reaction? 4NH3(g) + 6NO(g) → 5N2(g) + 6H2O(l) A) 165 g B) 132 g C) 125 g D) 206 g E) 7.35 g

D) 206 g

Which of the following gives the balanced equation for this reaction? K3PO4+ Ca(NO3)2 → Ca3(PO4)2+ KNO3 A) KPO4+ CaNO3+ KNO3 B) K3PO4+ Ca(NO3)2 → Ca3(PO4)2+ 3KNO3 C) 2K3PO4 + Ca(NO3)2 → Ca3(PO4)2+ 6KNO3 D) 2K3PO4+ 3Ca(NO3)2 → Ca3(PO4)2+ 6KNO3 E) K3PO4+ Ca(NO3)2 → Ca3(PO4)2+ KNO3term-24

D) 2K3PO4+ 3Ca(NO3)2 → Ca3(PO4)2+ 6KNO3

What is the molar mass of sucrose (C12H22O11)? A) 29.0 g B) 50.2 g C) 210 g D) 342 g E) 182 g

D) 342 g

The molar mass of potassium is A) 19 g. B) 31.0 g. C) 6.02 × 1023 grams. D) 39.1 g. E) 15g.

D) 39.1 g.

When 4 moles of aluminum are allowed to react with an excess of chlorine gas, Cl2, how many moles of aluminum chloride are produced? A) 1 mole B) 2 moles C) 3 moles D) 4 moles E) 5 moles

D) 4 moles

One mole of helium gas has a mass of A) 1.00 g. B) 2.00 g. C) 3.00 g. D) 4.00 g. E) 8.00 g.

D) 4.00 g.

When 10.0 g of NH3 reacts, the actual yield of N2 is 8.50 g. What is the percent yield? 4NH3(g) + 6NO(g) → 5N2(g) + 6H2O(l) A) 85.0% B) 51.5% C) 20.6% D) 41.3% E) 8.5%

D) 41.3%

What is the coefficient for water in the balanced equation? C5H12 + ? O2 → ? CO2+ ? H2O A) 2 B) 4 C) 5 D) 6 E) 8

D) 6

One mole of particles of any substance contains how many particles? A) 106 B) 3 × 10-10 C) 3 × 1010 D) 6.02 × 1023 E) 6.02 × 10-23

D) 6.02 × 1023

What coefficient is placed in front of O2 to complete the balancing of the following equation? C5H8+ ? O2 → 5CO2+ 4H2O A) 1 B) 3 C) 5 D) 7 E) 9

D) 7

How many grams of CO2 are produced from 125 g of O2 and excess CH4? CH4 + 2O2 → CO2 + 2H2O A) 125 g of CO2 B) 62.5 g of CO2 C) 172 g of CO2 D) 85.9 g of CO2 E) 250. g of CO2

D) 85.9 g of CO2

Mg3N2(s) + 6H2O(l) → 3Mg (OH)2(s) + 2NH3(g) 61) How many grams of H2O are needed to produce 150 g of Mg(OH)2? A) 46 g B) 18 g C) 130 g D) 93 g E) 23 g

D) 93 g

The following reaction takes place when an electric current is passed through water. It is an example of a ________ reaction. 2H2O → 2H2 + O2 A) combination B) single replacement C) dehydration D) decomposition E) double replacement

D) decomposition

The reaction of methane with oxygen to produce carbon dioxide and water is an example of which class of reaction? CH4(g) + 2O2(g) → CO2(g) + 2H2O(g) A) single replacement B) double replacement C) combination D) oxidation E) endothermic

D) oxidation

In an oxidation-reduction reaction, the substance reduced always A) takes on oxygen atoms. B) shows a loss of electrons. C) gives up hydrogen atoms. D) shows a gain of electrons. E) becomes a charged species.

D) shows a gain of electrons.

What is the classification for this unbalanced reaction? Fe + HCl → FeCl3 + H2 A) dehydration B) combination C) decomposition D) single replacement E) double replacement

D) single replacement

A chemical equation is balanced when A) the total number of molecules is the same in reactants and products. B) the total number of ions is the same in reactants and products. C) the sum of the coefficients of the reactants is equal to the sum of the coefficients of the products. D) the number of atoms of each element is the same in reactants and products. E) the charge on each atom is the same in reactants and products.

D) the number of atoms of each element is the same in reactants and products.

In this reaction, what is the substance oxidized? Zn(s) + 2 HCl(aq) → ZnCl2(aq) + H2(g) A) chlorine B) zinc chloride C) hydrogen D) zinc E) oxygen

D) zinc

When 2 moles of Mg3N2 are allowed to react, how many moles of H2O also react? A) 1 mole B) 4 moles C) 6 moles D) 8 moles E) 12 moles

E) 12 moles

What is the molar mass of Mg3(PO4)2, a substance formerly used in medicine as an antacid? A) 71.3 g B) 118 g C) 150. g D) 214 g E) 263 g

E) 263 g

1.25 moles of PbO2 have a mass of A) 191 g. B) 279 g. C) 178 g. D) 239 g. E) 299 g.

E) 299 g.

How many hydrogen atoms are present in 75.0 g of H2O? A) 75.0 atoms B) 4.17 atoms C) 7.53 × 10^24 atoms D) 2.51 × 10^24 atoms E) 5.02 × 10^24 atoms

E) 5.02 × 1024 atoms

Pentane (C5H12) reacts with oxygen (O2) to form carbon dioxide (CO2) and water (H2O) according to the following reaction. Answer the question(s) that follow about this reaction. C5H12 + ? O2 → ? CO2+ ? H2O 11) What is the coefficient for oxygen in the balanced equation? A) 2 B) 4 C) 5 D) 6 E) 8term-24

E) 8

4.00 moles of sodium have a mass of A) 4.60 g. B) 11.0 g. C) 23.0 g. D) 44.0 g. E) 92.0 g.

E) 92.0 g.

In a ________ reaction, two or more elements or compounds form one product. A) decomposition B) single replacement C) dehydration D) double replacement E) combination

E) combination

The ________ is the energy difference between reactants and products in a chemical reaction. A) transition energy B) activation energy C) product energy D) overall energy E) heat of reaction

E) heat of reaction

A reaction that releases energy as it occurs is classified as a(n) A) endothermic reaction. B) exothermic reaction. C) oxidation-reduction reaction. D) catalyzed reaction. E) decomposition reaction.

exothermic reaction.