Deck 3: Chemical Reactions and Earths Composition

Question 1

Hydrogen peroxide decomposes to produce water and oxygen. Which relationship regarding the quantities of reactants and products associated with this reaction is not correct? 2H₂O₂ $\rightarrow$ 2H₂O + O₂

A) 68.0 g $\rightarrow$ 36.0 g + 32.0 g
B) 34.0 g $\rightarrow$ 18.0 g + 16.0 g
C) 90.4 g $\rightarrow$ 47.9 g + 42.6 g
D) 2x g $\rightarrow$ 2x g + x g
E) y(34.0 g) $\rightarrow$ y(18.0 g) + (32 g)(y/2)

Answer 1

2x g $\rightarrow$ 2x g + x g

Question 2

A sample of water (H₂O) contains 1.81 * 10²⁴ molecules. How many moles of atoms are there in this sample?

A) 1.00
B) 2.00
C) 3.00
D) 6.00
E) 9.00

Answer 2

9.00

Question 3

How many oxygen atoms are there in 27.04 g of sodium sulfate (Na₂SO₄)?

A) 1.15 * 10²³ atoms
B) 4.58 * 10²³ atoms
C) 5.73 * 10²³ atoms
D) 2.41 * 10²⁴ atoms
E) 6.88 *10²³ atoms

Answer 3

4.58 * 10²³ atoms

Question 4

A tiny speck (8.3*10^-7 mol) of radioactive Americium-241 is used in smoke detectors. How many atoms of Americium-241 are there in one of these smoke detectors?

A) 5.0* 10¹⁷
B) 1.2 *10²⁰
C) 2.9* 10²²
D) 6.0 * 10²³
E) 8.3* 10⁷

Question 5

One mole is defined as __________

A) the number of particles equal to the number of atoms in exactly 12 g of carbon-12.
B) the number of particles equal to the number of atoms in exactly 16 g of oxygen-16.
C) 6.02 *10²².
D) the number of particles equal to the number of atoms in exactly 1 g of hydrogen-1.
E) the number of particles equal to the number of atoms in exactly 1 kg of carbon at the National Bureau of Standards.

Question 6

Which one of the following samples contains the fewest number of molecules? H is used as the symbol for hydrogen-1, and D is used as the symbol for hydrogen-2.

A) 42 g of D₂O
B) 2 moles of H₂O
C) 2 moles of D₂O
D) 36 g of H₂O
E) 39 g of D₂O

Question 7

What is the molar mass of sulfuric acid (H₂SO₄)?

A) 49.0 g/mol
B) 24.5 g/mol
C) 101 g/mol
D) 98.1 g/mol
E) 97.0 g/mol

Question 8

Which statement about a balanced chemical reaction equation is always correct?

A) The total number of moles of the products equals the total number of moles of the reactants.
B) The number of atoms of each kind is the same for the products as for the reactants.
C) The sum of the stoichiometric coefficients for the products equals the sum of the stoichiometric coefficients for the reactants.
D) The sum of the masses of all gaseous products equals the sum of the masses of the gaseous products.
E) The sum of the masses of solid products equals the sum of the masses of solid reactants.

Question 9

As a purchasing agent for a pharmaceutical company, how much chlorine, Cl₂, do you need to order to react completely with 500 kg of platinum, Pt, to make cisplatin, PtCl₂(NH₃)₂?

A) 182 kg
B) 500 kg
C) 2564 kg
D) 364 kg
E) 91 kg

Question 10

Which statement about the following chemical reaction is not correct? 3H₂ + N₂ $\rightarrow$ 2NH₃

A) For every nitrogen molecule consumed, two molecules of ammonia are produced.
B) For every two molecules of nitrogen consumed, three molecules of ammonia are produced.
C) For every three molecules of hydrogen consumed, two molecules of ammonia are produced.
D) For every two molecules of ammonia produced, three molecules of hydrogen are consumed.
E) One molecule of nitrogen reacts with three molecules of hydrogen.

Question 11

A tiny speck (2.0 *10^-4 g) of radioactive Americium-241 (241.06 g/mol) is used in smoke detectors. How many atoms of Americium-241 are there in one of these smoke detectors?

A) 5.0 * 10¹⁷ atoms
B) 1.2 *10²⁰ atoms
C) 2.9 *10²² atoms
D) 6.0 * 10²³ atoms
E) 8.3 *10⁷ atoms

Question 12

A gallon of water has a mass of 3.79 kg. How many moles of water (18.02 g/mol) is this?

A) 0.210 mol
B) 210 mol
C) 68.3 mol
D) 68,300 mol
E) 386 mol

Question 13

How many mL of C₁₆H₃₄ are needed to react with 0.05 mol O₂? The density of C₁₆H₃₄ is 0.80 g/mL.

A) 0.99 mL
B) 0.37 mL
C) 0.58 mL
D) 0.46 mL
E) 0.89 mL

Question 14

How many hydrogen atoms are there in a 346 g sample of pure ammonia (NH₃)?

A) 3.67 *10²⁵ atoms
B) 1.22 * 10²⁵ atoms
C) 60.9 atoms
D) 20.3 atoms
E) 4.89 *10²⁵ atoms

Question 15

What is the molar mass of phosphorus pentachloride (PCl₅)?

A) 177.25 g/mol
B) 190.30 g/mol
C) 208.22 g/mol
D) 172.75 g/mol
E) 202.82 g/mol

Question 16

Which of the following contains the largest number of atoms?

A) 1 mol water
B) 1 mol phosphorus trichloride
C) 1 mol dinitrogen pentoxide
D) 2 mol carbon monoxide
E) All of these contain the same number of atoms.

Question 17

How many moles of ammonia are there in a 346 g sample of pure NH₃ (17.03 g/mol)?

A) 0.0496 mol
B) 20.3 mol
C) 24.7 mol
D) 5930 mol
E) 3.46 mol

Question 18

How many atoms of chlorine are there in 25.0 g of calcium chloride (CaCl₂)?

A) 1.36 * 10²³ atoms
B) 2.67*10²⁴ atoms
C) 2.71 * 10²³ atoms
D) 1.95 * 10²³ atoms

Question 19

Which statement about the following chemical reaction is not correct? 3H₂ + N₂ $\rightarrow$ 2NH₃

A) For every mole of nitrogen consumed, two moles of ammonia are produced.
B) For every two moles of nitrogen consumed, three moles of ammonia are produced.
C) For every three moles of hydrogen consumed, two moles of ammonia are produced.
D) For every two moles of ammonia produced, three moles of hydrogen are consumed.
E) Three moles of hydrogen will react with one mole of nitrogen to produce ammonia.

Question 20

Hydrogen peroxide decomposes to produce water and oxygen. Which relationship regarding the quantities of reactants and products associated with this reaction is not correct? 2H₂O₂ $\rightarrow$ 2H₂O + O₂

A) 2 molecules $\rightarrow$ 2 molecules + 1 molecule
B) 2 mol $\rightarrow$ 2 mol + 1 mol
C) 68.0 g $\rightarrow$ 36.0 g + 32.0 g
D) 2x mol $\rightarrow$ 2x mol + x mol
E) y(34.0 g) $\rightarrow$ y(18.0 g) + y(32 g)

Question 21

If the combustion of fossil fuels adds about 5 *10¹² kg of carbon to the atmosphere as CO₂ each year, how much oxygen is required to produce this amount of carbon dioxide?

A) about 1.3 * 10¹² kg
B) about 1.3 * 10¹³ kg
C) about 2.6 *10¹² kg
D) about 2.6 * 10¹³ kg
E) about 6.7 *10¹² kg

Question 22

Fe₂O₃(s) and powdered aluminum can react with great output of heat to form molten iron and Al₂O₃. When this reaction equation is balanced, what are the stoichiometric coefficients in the following order: Fe₂O₃, Al, Fe, Al₂O₃?

A) 1, 1, 1, 1
B) 2, 2, 2, 2
C) 1, 2, 2, 1
D) 2, 1, 1, 2
E) 1, 1, 2, 2

Question 23

In a demonstration of the complete combustion of propane (C₃H₈) with oxygen (O₂), several balloons were prepared with various proportions by volume of propane and oxygen. The loudest explosion occurred for the balloon with the correct stoichiometric proportions of the gases. Which balloon had the loudest explosion?

A) 1 portion propane to 1 portion oxygen
B) 1 portion propane to 3 portions oxygen
C) 1 portion propane to 4 portions oxygen
D) 1 portion propane to 5 portions oxygen
E) 2 portions propane to 3 portions oxygen

Question 24

One form of elemental sulfur is a ring of eight sulfur atoms. How many moles of molecular oxygen are consumed when one mole of this allotrope burns to make sulfur trioxide?

A) 3
B) 6
C) 12
D) 18
E) 24

Question 25

What are the stoichiometric coefficients for oxygen and water, respectively, in the balanced chemical reaction equation representing the combustion of butane (C₄H₁₀)?

A) 4, 5
B) 9, 5
C) 13, 10
D) , 10
E) 13, 5

Question 26

Identify the set of stoichiometric coefficients that balance the reaction equation for the combustion of octane. C₈H₁₈ + O₂ $\rightarrow$ CO₂ + H₂O

A) 1, 25, 8, 9
B) 1, 17, 8, 9
C) 2, 34, 16, 18
D) 2, 25, 16, 18
E) None of the above coefficients balance the reaction equation.

Question 27

The average adult exhales about 1.0 kg of carbon dioxide each day. How much oxygen is needed in metabolizing glucose (C₆H₁₂O₆, 180 g/mol) to make that much carbon dioxide?

A) 180 g
B) 1800 g
C) 360 g
D) 730 g
E) 1500 g

Question 28

Diesel fuel for automobiles and trucks is a mixture of hydrocarbons that can be modeled by C₁₆H₃₄. Write the balanced reaction equation for the combustion of C₁₆H₃₄, and report the sum of the stoichiometric coefficients.

A) 4
B) 120
C) 76
D) 83
E) 117

Question 29

Which statement, A-D, regarding photosynthesis is not correct? In the process of photosynthesis __________

A) light energy is converted into carbon-based fuels.
B) oxygen is produced.
C) atmospheric carbon dioxide is consumed.
D) the sugar glucose is produced.
E) A-D are all correct.

Question 30

Ozone (O₃) reacts with iodide (I^-) and water to form iodine (I₂), hydroxide (OH^-), and oxygen (O₂). What is the sum of the stoichiometric coefficients in the balanced reaction equation? O₃ + I^- + H₂O $\rightarrow$ I₂ + OH^- + O₂

A) 10
B) 6
C) 8
D) 12
E) 14

Question 31

Which statement, A-D, regarding the carbon cycle is not correct?

A) Petroleum, coal, and other carbon sediments are produced.
B) Respiration produces atmospheric carbon dioxide.
C) Water is a reactant in photosynthesis.
D) Forest fires are part of the carbon cycle.
E) A-D are all correct.

Question 32

Air bags in cars inflate when an electrical spark activates sodium azide (NaN₃), so that it decomposes to sodium metal, Na, and nitrogen gas, N₂. In the balanced reaction equation, how many moles of nitrogen gas are formed for each mole of sodium azide?

A) 1
B) 1.5
C) 2
D) 3
E) 2.5

Question 33

The acid-base reaction between phosphoric acid, H₃PO₄, and calcium hydroxide, Ca(OH)₂, yields water and calcium phosphate. For each mole of calcium phosphate produced by this reaction, how many moles of water are produced?

A) 1
B) 2
C) 3
D) 4
E) 6

Question 34

Fuming sulfuric acid is obtained by the addition of SO₃ to concentrated H₂SO₄. The fumes result from the reaction of SO₃ gas with water vapor. What is the product when one molecule of SO₃ reacts with one molecule of water?

A) two molecules of sulfurous acid
B) one sulfate ion
C) two sulfite ions
D) one molecule of sulfuric acid
E) two molecules of sulfuric acid

Question 35

Glucose (C₆H₁₂O₆) is oxidized by molecular oxygen to carbon dioxide and water. How many O₂ molecules are needed for each molecule of glucose that is oxidized?

A) 1
B) 2
C) 6
D) 12
E) 18

Question 36

The combustion of ethanol (CH₃CH₂OH, 46.1 g/mol) results in the formation of water and carbon dioxide. How many grams of carbon dioxide are produced when 46.1 g of ethanol burns?

A) 88.0 g
B) 44.0 g
C) 176 g
D) 22.0 g
E) 11.0 g

Question 37

A fuel cell works on the same principle as a battery but is continually fed with fuel. In one fuel cell, methanol (CH₃OH) enters on one side of the unit, and air enters on the other side. Both circulate past electrodes, and a chemical reaction occurs that produces electricity plus carbon dioxide and water as byproducts. Which chemical reaction equation best represents the reaction that occurs in this fuel cell?

A) CH₃OH $\rightarrow$ CO₂ + H₂O
B) CH₃OH $\rightarrow$ CH₃ + OH
C) CH₃OH $\rightarrow$ CH₂ + H₂O
D) CH₃OH + O₂ $\rightarrow$ CO₂ + H₂O
E) 2CH₃OH + 3O₂ $\rightarrow$ 2CO₂ + 4H₂O

Question 38

A balanced chemical reaction equation is to a reactant as __________

A) a map is to a gas station.
B) a child is to a parent.
C) a recipe is to an ingredient.
D) a good job is to a college degree.
E) a paycheck is to a job.

Question 39

Sulfur dioxide from coal-fired power plants combines with water in the atmosphere to produce acid rain. What is the product when one molecule of SO₂ reacts with one molecule of water?

A) two molecules of sulfurous acid
B) one sulfate ion
C) two sulfite ions
D) one molecule of sulfuric acid
E) one molecule of sulfurous acid

Question 40

The combustion of butane (C₄H₁₀) forms carbon dioxide and water. What is the stoichiometric coefficient for oxygen in the balanced equation when 1 mol of butane undergoes combustion?

A) 9
B) 13
C)
D)
E) 5

Question 41

An iron ore, magnetite, contains only iron and oxygen. In refining 100.0 g of the ore, 72.35 g of iron are obtained. What is the empirical formula of the ore?

A) Fe₂O₃
B) FeO₂
C) Fe₂O₅
D) Fe₃O₄
E) FeO

Question 42

Hydrogen peroxide (H₂O₂) decomposes catalytically in the presence of metal ions and enzymes called peroxidases. You may have noticed this reaction occurring if you use a drugstore solution of hydrogen peroxide as a mouthwash or antiseptic. If a 250 mL bottle of hydrogen peroxide solution containing 3.0% H₂O₂ (by mass) completely decomposes, how many liters of oxygen gas would it generate? Assume that 1 mol of gas occupies a volume of 22.4 L and that the density of the solution is 1.0 g/mL. The reaction is 2H₂O₂(aq) $\rightarrow$ 2H₂O( ) + O₂(g)

A) 2.5 L
B) 4.9 L
C) 9.9 L
D) 7.4 L
E) 0.22 L

Question 43

A gas is produced when fruit ripens; that gas can be used in mixtures with nitrogen gas to ripen bananas just before they are put on the grocery shelf. This mixture is sold as banana gas. The mass percentages of carbon and hydrogen in this gas are 85.62% for C and 14.38% for H. The molar mass was found to be twice the empirical formula unit molar mass. What is the molecular formula of this gas?

A) CH₂
B) C₂H₂
C) C₂H₄
D) C₂H₆
E) C₄H₄

Question 44

Baking ammonia or ammonium bicarbonate (NH₄HCO₃, 79.1 g/mol) is a leavening agent used in some older recipes. As it is heated, it breaks down into three gases: ammonia, water, and carbon dioxide. For each 20 g of baking ammonia heated (about 4 tsp), how many grams of carbon dioxide are produced?

A) 15 g
B) 7.5 g
C) 11 g
D) 22 g
E) 20 g

Question 45

The average adult exhales about 1.0 kg of carbon dioxide each day. How much glucose (C₆H₁₂O₆, 180 g/mol) is consumed to make that much carbon dioxide?

A) 3.8 kg
B) 4.1 kg
C) 0.43 kg
D) 0.68 kg
E) 0.18 kg

Question 46

Baking soda (NaHCO₃, 84.0 g/mol) requires acids from other ingredients to generate the carbon dioxide needed to make bread rise. The following equation describes this reaction where HB is some unspecified acid. If 20.4 g of baking soda are used in a recipe and enough acid is present for a complete reaction, how many moles of carbon dioxide are generated? HB + NaHCO₃ $\rightarrow$ H₂O + CO₂ + NaB

A) 0.464 mol
B) 0.334 mol
C) 0.243 mol
D) 0.204 mol
E) 0.232 mol

Question 47

When are an empirical formula and a molecular formula the same?

A) Always
B) When the mass of the empirical formula unit is equal to the molecular mass
C) When the mass percentages of all of the elements in the two formulas are the same
D) Never
E) When the molecular mass is an integer multiple of formula unit mass

Question 48

The empirical formula for buckminsterfullerene is C₁, and its molar mass is 720.6 g/mol. What is its molecular formula?

A) C₆₀
B) C₇₂
C) C₁₂
D) C₁
E) C₇₂₀

Question 49

Arizona was the site of a 400,000-acre wildfire in June 2002. How much carbon dioxide was produced by this fire? Assume that the density of carbon on the acreage was 10 kg/m² and that 50% of the biomass burned (10,000 m² = 2.47 acre)

A) 3 * 10¹⁰ kg
B) 3* 10⁶ kg
C) 3*10³⁰ kg
D) 3 *10⁹ kg
E) 3 * 10¹³ kg

Question 50

How much CO₂ is produced by a car driven 20,000 mi in one year? Assume the following:
• A car gets 20 mi/4.0 L of gasoline.
• Gasoline has the chemical formula of octane: C₈H₁₈.
• One liter of gasoline has a mass of 0.8 kg.
• Gasoline is completely burned to carbon dioxide and water.

A) 1,500 kg
B) 9,900 kg
C) 15,000 kg
D) 20,000 kg
E) 4,900 kg

Question 51

Metallic copper can be obtained from the mineral chalcocite (Cu₂S). What is the mass percent of copper in chalcocite?

A) 79.85%
B) 66.46%
C) 20.15%
D) 33.54%
E) 57.47%

Question 52

Phthalocyanine is a large molecule used in printing inks and dyes for clothing due to its insolubility in most solvents, its chemical stability, and its intense blue color. Elemental analysis showed that it consists of 74.69% C, 3.525% H, and 21.77 % N, and has a molar mass of 514.54 g/mol. What is the molecular formula for phthalocyanine?

A) C₁₆H₉N₄
B) C₃₀H₈N₁₀
C) C₃₂H₁₈N₈
D) C₃₂H₄N₉
E) C₁₆H₁₈N₄

Question 53

The most abundant metal in Earth's crust is aluminum, found mostly in the form of clays. There are no economical routes for extracting aluminum from clay. However, bauxite ore, impure hydrated aluminum oxide, is found in hot humid regions, such as Australia, Guinea, and Brazil, and it can be purified and refined to make the metal. After the first purification step, hydrated aluminum oxide (Al₂O₃ . xH₂O) is obtained. When 100.0 g of this solid was heated, and the water driven off, 65.36 g of Al₂O₃ remained. How many water molecules (x in the molecular formula) were there in the hydrate?

A) 1
B) 2
C) 3
D) 4
E) 5

Question 54

A compound known to contain platinum, nitrogen, and hydrogen was analyzed and found to contain 74.1% Pt and 21.3% N; the remainder was hydrogen. What is the empirical formula for the compound?

A) Pt(NH₃)₄
B) Pt(NH₃)₃
C) Pt₂(NH₃)₂
D) Pt(NH₄)₂
E) Pt(NH₃)₆

Question 55

What mass of phosphoric acid (H₃PO₄, 98.0 g/mol) is produced from the reaction of 10.0 g of P₄O₁₀ (284 g/mol) with excess water?

A) 10.9 g
B) 40.0 g
C) 10.0 g
D) 13.8 g
E) 2.50 g

Question 56

Copper was the first metal to be produced from its ore because it is the easiest to smelt, that is, to refine by heating in the presence of carbon (hence the early occurrence of the Bronze Age). The ore was likely malachite [Cu₂(OH)₂CO₃]. What is the mass percent of copper in malachite?

A) 28.7%
B) 45.2%
C) 57.5%
D) 40.3%
E) 74.6%

Question 57

The space shuttle uses liquid hydrogen and liquid oxygen to produce thrust for liftoff in the following reaction. If the liquid oxygen supply is set to provide 420 kg/s during a launch, what does the rate of liquid hydrogen supply need to be in kilograms per second? 2H₂(l) + O₂( ) $\rightarrow$ 2H₂O(g)

A) 840 kg/s
B) 210 kg/s
C) 106 kg/s
D) 52.9 kg/s
E) 63.4 kg/s

Question 58

Caffeine has an elemental analysis of 49.48% carbon, 5.190% hydrogen, 16.47% oxygen, and 28.85% nitrogen. It has a molar mass of 194.19 g/mol. What is the molecular formula of caffeine?

A) C₄H₅N₂O
B) C₈H₁₀N₄O₂
C) C₁₀H₁₄N₂O₂
D) C₆H₆NO₂
E) C₅H₇NO

Question 59

Copper sulfate is a blue solid that is used to control algae growth. Solutions of copper sulfate that come in contact with the surface of galvanized (zinc-plated) steel pails undergo the following reaction that forms copper metal on the zinc surface. How many grams of zinc would react with 454 g (1 lb) of copper sulfate (160 g/mol)? CuSO₄(aq) + Zn(s) $\rightarrow$ Cu(s) + ZnSO₄(aq)

A) 467 g
B) 186 g
C) 93 g
D) 234 g
E) 454 g

Question 60

Water can be separated into its elements according to the following equation by electrolysis. If 20.0 g of water is decomposed by this method, how much oxygen gas is produced? 2H₂O ( ) $\rightarrow$ 2H₂(g) + O₂(g)

A) 17.8 g
B) 8.9 g
C) 35.6 g
D) 16.0 g
E) 10.0 g

Question 61

A copper ore consisting of 12.5% copper(II) sulfide, when heated and reacted with oxygen gas, produces copper(II) oxide and sulfur dioxide. If the reaction has a 90.0% yield, how many grams of copper(II) oxide are produced when 1.00 kg of the copper ore is processed?

A) 93.7 g
B) 104 g
C) 116 g
D) 150 g
E) 749 g

Question 62

A hydrocarbon molecule contains carbon and hydrogen atoms in equal numbers. Its molar mass is 130.18 g/mol. What is the molecular formula for the hydrocarbon?

A) C₇H₇
B) C₁₂H₁₂
C) C₈H₈
D) C₁₀H₁₀
E) CH

Question 63

A careless student who was instructed to combine 4.00 g of sodium sulfate with a solution containing 10.0 g of H₂SO₄ (98.08 g/mol) instead combined 4.00 g of sodium sulfide (78.05 g/mol) with the acid. The acid reacted with the sodium sulfide, according to the following reaction, to produce the foul-smelling and highly toxic hydrogen sulfide gas. How many moles of hydrogen sulfide gas were produced? Na₂S(s) + H₂SO₄(aq) $\rightarrow$ Na₂SO₄(aq) + H₂S(g)

A) 0.0510 mol
B) 0.102 mol
C) 0.0512 mol
D) 0.0257 mol
E) 0.0315 mol

Question 64

Combustion analysis of an organic compound to determine the percentages of carbon, hydrogen, and oxygen in the compound depends on which of the following assumptions?

A) The compound burns completely to form carbon dioxide and water.
B) All the oxygen in the products comes from the added oxygen gas.
C) The mass of the carbon dioxide produced equals the mass of the carbon in the sample.
D) The moles of water produced equal the moles of hydrogen in the sample.
E) The mass of oxygen in the sample is the difference between the mass of the sample and the sum of the masses of carbon dioxide and water produced.

Question 65

U.S. Lime & Minerals is a company that produces quicklime, CaO, by heating calcium hydroxide, Ca(OH)₂. What is the percent yield if 45 grams of quicklime are obtained from 1 mole of calcium hydroxide?

A) 61%
B) 80%
C) 45%
D) 100%
E) 90%

Question 66

A reaction vessel contains equal masses of iron and oxygen. How much FeO could theoretically be produced?

A) an amount equal to the sum of the masses of iron and oxygen
B) an amount greater than the sum of the masses of iron and oxygen
C) an amount less than the sum of the masses of iron and oxygen
D) There is no way to tell.
E) It depends on the reaction conditions.

Question 67

Allicin, a potent antibacterial compound, is formed by the enzyme alliinase when garlic is chopped or damaged. Allicin contains carbon, hydrogen, oxygen, and sulfur atoms. In combustion analysis, a 10.00 mg sample of allicin produced 16.27 mg of CO₂, 5.55 mg of water, and 7.90 mg of SO₂. What is the empirical formula of allicin?

A) C₆H₁₀S₂O
B) C₃H₅SO
C) C₁₂H₂₀S₄O
D) C₆H₁₀SO
E) The moles of oxygen in the sample cannot be determined, so the empirical formula cannot be determined.

Question 68

A bottle containing 1665 g of sulfuric acid (H₂SO₄, 98.08 g/mol) was spilled in a laboratory. The emergency spill kit contained a full 2.0 kg bottle of sodium carbonate (105.99 g/mol). Is this enough sodium carbonate to neutralize the acid according to the following reaction? H₂SO₄(aq) + Na₂CO₃(s) $\rightarrow$ Na₂SO₄(aq) + CO₂(g) + H₂O( )

A) Yes, there is about 50% more than what is needed.
B) Yes, there is exactly enough sodium carbonate, but no excess.
C) No, there is not enough sodium carbonate, but the amount is only about 10% too small.
D) No, there is not nearly enough sodium carbonate.
E) Yes, but there is only about 10% excess.

Question 69

A mass of 11.60 g of phosphoric acid was produced from the reaction of 10.00 g of P₄O₁₀ with 12.0 g water. What was the percent yield for this reaction?

A) 78.62%
B) 101.1%
C) 92.70%
D) 84.00%
E) 52.70%

Question 70

Ammonia, NH₃, is an important industrial chemical. It is produced using the Haber process from nitrogen, N₂, and hydrogen, H₂. How much ammonia can be produced from 28 kg of nitrogen and 2 kg of hydrogen, assuming the reaction yield is 90%?

A) 10.2 kg
B) 11.3 kg
C) 17.0 kg
D) 34.0 kg
E) 9.95 kg

Question 71

You are given a liquid sample that contains either methanol, ethanol, or a mixture of both. You use combustion analysis of a 0.336 g sample and obtain 0.462 g of CO₂. What did you learn about your sample?

A) It is methanol.
B) It is ethanol.
C) It is more methanol than ethanol.
D) It is more ethanol than methanol.
E) It contains equal amounts of methanol and ethanol.

Question 72

Household bleach contains 5.0% sodium hypochlorite (NaOCl) by mass. Household ammonia contains 5.0% NH₃ by mass. If 50.00 g of bleach are mixed with 50.00 g of 5.0% ammonia, what mass of the toxic chloramine gas would be produced by the following reaction? NaOCl + NH₃ $\rightarrow$ NH₂Cl + NaOH

A) 5.0 g
B) 2.5 g
C) 1.7 g
D) 7.6 g
E) 3.2 g

Question 73

What is the mass in amu of one molecule of glucose, C₆H₁₂O₆?

Question 74

Chemical analysis of an organic compound found the following composition: 40.0% C, 53.5% O, and 6.7% H. If the molar mass is 180.2 g/mol, how many empirical formula units are there in the molecular formula?

A) 2
B) 4
C) 8
D) 6
E) 7

Question 75

Socrates was killed by a dose of hemlock, which is a poisonous herb in the carrot family. In a combustion experiment, 50.05 mg of the poisonous compound in hemlock was burned in excess oxygen to give 140.8 mg of CO₂ and 54.2 mg of H₂O. In a second experiment, it was determined that the compound is composed of only carbon, hydrogen, and nitrogen and has a molar mass less than 200 g/mol. What is the molecular formula of the poisonous compound in hemlock? Respond with the sum of the C, N, and H atoms in this compound. For example, if the molecular formula were CNH₂, you would respond 4.

A) 18
B) 12
C) 24
D) 36
E) 30

Question 76

What mass of phosphoric acid (H₃PO₄, 98.00 g/mol) is produced from the reaction of 10.00 g of P₄O₁₀ (283.89 g/mol) with 12.00 g water?

A) 10.90 g
B) 0.14 g
C) 43.52 g
D) 13.81 g
E) 14.52 g

Question 77

Write a definition of the term molar mass.

Question 78

Calcium hydride (CaH₂) is so reactive with water that it can be used to remove traces of water from solvents other than water. If 24.6 g of calcium hydride is added to a large volume of solvent that contains 14.0 g of water, which of these remains, water or calcium hydride, after the reaction is complete? The reaction is: CaH₂(s) + 2H₂O( ) $\rightarrow$ Ca(OH)₂(s) + 2H₂(g)

A) CaH₂ will be left over.
B) Water will be left over.
C) Both will be completely consumed.
D) There is no way to tell.

Question 79

How many atoms are there in one mole of water?

Question 80

Dialuminum hexachloride, Al₂Cl₆, is an inexpensive compound that is used in many industrial processes. It is made by treating scrap aluminum with chlorine gas. If a reaction is run with 270 g of aluminum and 710 grams of chlorine, the limiting reactant is __________, and the theoretical yield is __________ grams of Al₂Cl₆. 2Al(s) + 3Cl₂(g) $\rightarrow$ Al₂Cl₆(s)

A) Al, 890 g
B) Cl, 890 g
C) Al, 1335 g
D) Cl, 1335 g
E) Cl, 2670 g