Question 1

A gallon of water has a mass of 3.79 kg.How many moles of water is this?

Accepted Answer

A) 2.10 *102 mol 
B) 0.210 mol 
C) 68.3 mol 
D) 6.83 * 104 mol 
E) 386 mol 
A) 2.10 *102 mol 
B) 0.210 mol 
C) 68.3 mol 
D) 6.83 * 104 mol 
E) 386 mol A

Question 2

During fermentation, yeast converts glucose (180.2 g/mol) into ethanol (46.08 g/mol) and carbon dioxide (44.01 g/mol).The unbalanced reaction equation is given below.Balance the equation and find the percent yield for the reaction if 150.0 g of glucose yields 75.0 mL of ethanol (d =0.789 g/mL).
C6 H12 O6 (aq) $\rightarrow$ C2 H5 OH(aq) + CO2 (g)

Accepted Answer

C₆ H₁₂ O₆ (aq) $\rightarrow$ 2C₂ H₅ OH(aq) + 2 CO₂ (g), percent yield = 77.1%

Question 3

Gold metal will dissolve in an aqueous sodium cyanide solution in the presence of O2. Balance the equation showing this process.
____Au(s)+____ NaCN(aq)+ ____O2 (g)+ ____H2 O(l)  $\rightarrow$ ___NaAu(CN)2 (aq)+_____ NaOH(aq)

Accepted Answer

4Au(s) + 8 NaCN(aq) +O₂ (g) +2H₂ O(l) $\rightarrow$ 4 NaAu(CN)₂(aq) + 4 NaOH(aq)

Question 4

Metallic chromium can be obtained from the mineral chromite (FeCr2O4).What is the mass percent of chromium in chromite?

Accepted Answer

A) 46.46% 
B) 61.90% 
C) 23.23% 
D) 30.26% 
E) 41.99% 
A) 46.46% 
B) 61.90% 
C) 23.23% 
D) 30.26% 
E) 41.99%

Question 5

List three reasons why the actual yield for a chemical reaction may differ from the theoretical yield.

Accepted Answer

1) The reactants and products reach an e

Question 6

Which statement regarding the carbon cycle is FALSE?

Accepted Answer

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) Combustion produces atmospheric oxygen. 
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) Combustion produces atmospheric oxygen.

Question 7

Fill in the following table regarding the following reaction.
$ \mathrm{UO}_{2}(s)+4 \mathrm{HF}(a q) \rightarrow \mathrm{UF}_{4}(s)+2 \mathrm{H}_{2} \mathrm{O}(\ell) $

Accepted Answer

The answer of Fill in the following table regarding the...

Question 8

For which of the following compounds are the empirical and molecular formulas the same? 
Acetic acid, found in vinegar, CH3COOH
Formaldehyde, used to preserve biological specimens, CH2O
Ethanol, found in beer and wine, CH3CH2OH

Accepted Answer

Formaldehy

Question 9

Which statement about the following chemical reaction is NOT correct?
 3 H2 (g) + N2 (g) $\rightarrow$2 NH3 (g)

Accepted Answer

A) For every two moles of nitrogen consumed, three moles of ammonia are produced. 
B) For every mole of nitrogen consumed, two 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. 
A) For every two moles of nitrogen consumed, three moles of ammonia are produced. 
B) For every mole of nitrogen consumed, two 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 10

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).

Accepted Answer

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

Question 11

Elemental phosphorus (123.88 g/mol) reacts vigorously with halogens at room temperature to produce phosphorus trihalides.What is the theoretical yield in grams) of PF 3 (87.97 g/mol) when 15.0 g P4 reacts with 25.0 g F2 (38.00 g/mol)?
P4 (s) +6 F2 (g) $\rightarrow$ 4 PF3 (g)

Accepted Answer

The answer of Elemental phosphorus (123.88 g/mol) reacts vigorously with...

Question 12

Diethyl azodicarboxylate, or DEAD, is an explosive compound with the empirical formula C3H5NO2 and a molecular mass of approximately 174 amu.Find its molecular formula.

Accepted Answer

Question 13

Which of the following does NOT share the same empirical formula as the others?

Accepted Answer

A) formaldehyde, CH2O 
B) acetic acid, CH3COOH 
C) lactic acid, CH3CH(OH)COOH 
D) butyric acid, CH3CH2CH2COOH 
E) glucose, C6H12O6 
A) formaldehyde, CH2O 
B) acetic acid, CH3COOH 
C) lactic acid, CH3CH(OH)COOH 
D) butyric acid, CH3CH2CH2COOH 
E) glucose, C6H12O6

Question 14

Which statement about the following chemical reaction is NOT correct? The molar masses of S8, O2, and SO3 are 256, 32.0, and 80.1 g/mol, respectively. 
S8 (s)+ 12 O2 (g) $\rightarrow$ 8 SO3 (g)

Accepted Answer

A) 1 mol S8 produces 8 mol SO3. 
B) 256 g S8 requires 12 mol O2 in order to completely react. 
C) In order to produce 8 mol SO3, 256 g S8 and 192 g O2 must react. 
D) For every 6 mol O2 consumed, 4 mol SO3 are produced. 
E) If 641 g SO3 are produced, a total mass of 641 g of S8 and O2 must react. 
A) 1 mol S8 produces 8 mol SO3. 
B) 256 g S8 requires 12 mol O2 in order to completely react. 
C) In order to produce 8 mol SO3, 256 g S8 and 192 g O2 must react. 
D) For every 6 mol O2 consumed, 4 mol SO3 are produced. 
E) If 641 g SO3 are produced, a total mass of 641 g of S8 and O2 must react.

Question 15

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

Accepted Answer

A) 177.3 g/mol 
B) 190.3 g/mol 
C) 208.2 g/mol 
D) 172.8 g/mol 
E) 202.8 g/mol 
A) 177.3 g/mol 
B) 190.3 g/mol 
C) 208.2 g/mol 
D) 172.8 g/mol 
E) 202.8 g/mol

Question 16

What mass of nitrogen gas (28.02 g/mol) is produced when 0.500 kg I2 (253.8 g/mol) is combined with 35.0 g N2H4 32.06 g/mol)? 
2 I2(s) + N2H4 (g)  $\rightarrow$  4 HI(g) + N2(g)

Accepted Answer

A) 27.6 g 
B) 34.0 g 
C) 55.2 g 
D) 32.6 g 
E) 16.3 g 
A) 27.6 g 
B) 34.0 g 
C) 55.2 g 
D) 32.6 g 
E) 16.3 g

Question 17

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

Accepted Answer

A) 49.0 g/mol 
B) 24.5 g/mol 
C) 101 g/mol 
D) 98.1 g/mol 
E) 97.0 g/mol 
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 18

Without doing any calculations, identify which of the following compounds has the largest percent sodium by mass and which has the smallest.Explain your logic.
sodium oxide, Na2O; sodium hydroxide, NaOH; sodium hydrogen carbonate, NaHCO3; sodium carbonate, Na2CO3; sodium peroxide, Na2O2

Accepted Answer

Largest: Na₂O.One molecule has two Na ato

Question 19

Hydrogen peroxide decomposes to produce water and oxygen.Which relationship regarding the quantities of reactants and products associated with this reaction is NOT correct?
 2H2 O2 (l) $\rightarrow$ 2H2 O(l) + O2 (g)

Accepted Answer

A) 68.0 g $\rightarrow$36.0 g + 32.0 g 
B) 34.0 g $\rightarrow$ 18.0 g + 16.0 g 
C) 90.5 g (\rightarrow\) 47.9 g + 42.6g 
D) 2 x g $\rightarrow$ 2 x g + x g 
E) y(34.0g) $\rightarrow$ y(18.0g) +(y / 2)(32g) 
A) 68.0 g $\rightarrow$36.0 g + 32.0 g 
B) 34.0 g $\rightarrow$ 18.0 g + 16.0 g 
C) 90.5 g (\rightarrow\) 47.9 g + 42.6g 
D) 2 x g $\rightarrow$ 2 x g + x g 
E) y(34.0g) $\rightarrow$ y(18.0g) +(y / 2)(32g)

Question 20

What is the difference in the chemistry between photosynthesis and respiration? Show the chemical equations for each.Which one releases energy? Which one stores energy?

Accepted Answer

In photosynthesis, carbon dioxide and wa

Exam 7: Stoichiometry Mass Relationships and Chemical Reactions

A gallon of water has a mass of 3.79 kg.How many moles of water is this?

Gold metal will dissolve in an aqueous sodium cyanide solution in the presence of O2. Balance the equation showing this process. ____Au(s)+____ NaCN(aq)+ ____O2 (g)+ ____H2 O(l) →\rightarrow→ ___NaAu(CN)2 (aq)+_____ NaOH(aq)

Metallic chromium can be obtained from the mineral chromite (FeCr2O4).What is the mass percent of chromium in chromite?

List three reasons why the actual yield for a chemical reaction may differ from the theoretical yield.

Which statement regarding the carbon cycle is FALSE?

Fill in the following table regarding the following reaction. UO2(s)+4HF(aq)→UF4(s)+2H2O(ℓ) \mathrm{UO}_{2}(s)+4 \mathrm{HF}(a q) \rightarrow \mathrm{UF}_{4}(s)+2 \mathrm{H}_{2} \mathrm{O}(\ell) UO2​(s)+4HF(aq)→UF4​(s)+2H2​O(ℓ)

For which of the following compounds are the empirical and molecular formulas the same? Acetic acid, found in vinegar, CH3COOH Formaldehyde, used to preserve biological specimens, CH2O Ethanol, found in beer and wine, CH3CH2OH

Which statement about the following chemical reaction is NOT correct? 3 H2 (g) + N2 (g) →\rightarrow→ 2 NH3 (g)

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).

Elemental phosphorus (123.88 g/mol) reacts vigorously with halogens at room temperature to produce phosphorus trihalides.What is the theoretical yield in grams) of PF 3 (87.97 g/mol) when 15.0 g P4 reacts with 25.0 g F2 (38.00 g/mol)? P4 (s) +6 F2 (g) →\rightarrow→ 4 PF3 (g)

Diethyl azodicarboxylate, or DEAD, is an explosive compound with the empirical formula C3H5NO2 and a molecular mass of approximately 174 amu.Find its molecular formula.

Which of the following does NOT share the same empirical formula as the others?

Which statement about the following chemical reaction is NOT correct? The molar masses of S8, O2, and SO3 are 256, 32.0, and 80.1 g/mol, respectively. S8 (s)+ 12 O2 (g) →\rightarrow→ 8 SO3 (g)

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

What mass of nitrogen gas (28.02 g/mol) is produced when 0.500 kg I2 (253.8 g/mol) is combined with 35.0 g N2H4 32.06 g/mol)? 2 I2(s) + N2H4 (g) →\rightarrow→ 4 HI(g) + N2(g)

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

Without doing any calculations, identify which of the following compounds has the largest percent sodium by mass and which has the smallest.Explain your logic. sodium oxide, Na2O; sodium hydroxide, NaOH; sodium hydrogen carbonate, NaHCO3; sodium carbonate, Na2CO3; sodium peroxide, Na2O2

Hydrogen peroxide decomposes to produce water and oxygen.Which relationship regarding the quantities of reactants and products associated with this reaction is NOT correct? 2H2 O2 (l) →\rightarrow→ 2H2 O(l) + O2 (g)

What is the difference in the chemistry between photosynthesis and respiration? Show the chemical equations for each.Which one releases energy? Which one stores energy?

Matter and Energy an Atomic Perspective

Atoms, Ions, and Molecules the Building Blocks of Matter

Atomic Structure Explaining the Properties of Elements

Chemical Bonding Understanding Climate Change

Bonding Theories Explaining Molecular Geometry

Intermolecular Forces Attractions Between Particles

Aqueous Solutions Chemistry of the Hydrosphere

Thermochemistry Energy Changes in Chemical Reactions

Properties of Gases the Air We Breathe

Properties of Solutions Their Concentrations and Colligative Properties

Thermodynamics Why Chemical Reactions Happen

Chemical Kinetics Clearing the Air

Chemical Equilibrium Equal but Opposite Reaction Rates

Acid-Base Equilibria Proton Transfer in Biological Systems

Additional Aqueous Equilibria Chemistry and the Oceans

Electrochemistry the Quest for Clean Energy

The Solid State a Particulate View

Organic Chemistry Fuels, Pharmaceuticals, and Modern Materials

Biochemistry the Compounds of Life

Nuclear Chemistry the Risks and Benefits

The Main Group Elements Life and the Periodic Table

Transition Metals Biological and Medical Applications

Filters

Gold metal will dissolve in an aqueous sodium cyanide solution in the presence of O₂. Balance the equation showing this process. __Au(s)+ NaCN(aq)+ O₂ (g)+ H₂ O(l) $\rightarrow$ _NaAu(CN)₂ (aq)+_____ NaOH(aq)

Metallic chromium can be obtained from the mineral chromite (FeCr₂O₄).What is the mass percent of chromium in chromite?

For which of the following compounds are the empirical and molecular formulas the same? Acetic acid, found in vinegar, CH₃COOH Formaldehyde, used to preserve biological specimens, CH₂O Ethanol, found in beer and wine, CH₃CH₂OH

Which statement about the following chemical reaction is NOT correct? 3 H₂ (g) + N₂ (g) $\rightarrow$ 2 NH₃ (g)

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).

Elemental phosphorus (123.88 g/mol) reacts vigorously with halogens at room temperature to produce phosphorus trihalides.What is the theoretical yield in grams) of PF ₃ (87.97 g/mol) when 15.0 g P₄ reacts with 25.0 g F₂ (38.00 g/mol)? P₄(s) +6 F₂ (g) $\rightarrow$ 4 PF₃ (g)

Diethyl azodicarboxylate, or DEAD, is an explosive compound with the empirical formula C₃H₅NO₂ and a molecular mass of approximately 174 amu.Find its molecular formula.

Which statement about the following chemical reaction is NOT correct? The molar masses of S₈, O₂, and SO₃ are 256, 32.0, and 80.1 g/mol, respectively. S₈ (s)+ 12 O₂ (g) $\rightarrow$ 8 SO₃ (g)

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

What mass of nitrogen gas (28.02 g/mol) is produced when 0.500 kg I₂ (253.8 g/mol) is combined with 35.0 g N₂H₄ 32.06 g/mol)? 2 I₂(s) + N₂H₄ (g) $\rightarrow$ 4 HI(g) + N₂(g)

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

Without doing any calculations, identify which of the following compounds has the largest percent sodium by mass and which has the smallest.Explain your logic. sodium oxide, Na₂O; sodium hydroxide, NaOH; sodium hydrogen carbonate, NaHCO₃; sodium carbonate, Na₂CO₃; sodium peroxide, Na₂O₂

Hydrogen peroxide decomposes to produce water and oxygen.Which relationship regarding the quantities of reactants and products associated with this reaction is NOT correct? 2H₂ O₂ (l) $\rightarrow$ 2H₂ O(l) + O₂ (g)