Question 1

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

Question 2

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 3

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

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%

Question 5

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

Question 6

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 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

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 10

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)

Question 11

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 12

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.

Question 13

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

Question 14

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.

Question 15

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...

Question 16

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 17

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

Question 18

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.

Question 19

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 20

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

Exam 7: Stoichiometry Mass Relationships and Chemical Reactions

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)

Correct Answer
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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

Correct Answer
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Largest: Na₂O.One molecule has two Na ato...
View Answer

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

Correct Answer
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A

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

Correct Answer
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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) .

Correct Answer
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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)

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

Correct Answer
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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

Correct Answer
verified
Formaldehy...
View Answer

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

Correct Answer
verified
1) The reactants and products reach an e...
View Answer

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)

Correct Answer
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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.

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

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

Correct Answer
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Which statement regarding the carbon cycle is FALSE?

Correct Answer
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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?

Correct Answer
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In photosynthesis, carbon dioxide and wa...
View Answer

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)

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

Correct Answer
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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)

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

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

Correct Answer
verified

Exam 7: Stoichiometry Mass Relationships and Chemical Reactions

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)

Correct AnswerverifiedShow Answer

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

Correct AnswerverifiedLargest: Na2O.One molecule has two Na ato...View AnswerShow Answer

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

Correct AnswerverifiedA

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

Correct AnswerverifiedShow Answer

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) .

Correct AnswerverifiedShow Answer

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)

Correct Answerverified4Au(s) + 8 NaCN(aq) +O2 (g) +2H2 O(l) \(\rightarrow\) 4 NaAu(CN)2 (aq) + 4 NaOH(aq)

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)

Correct AnswerverifiedShow Answer

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

Correct AnswerverifiedFormaldehy...View AnswerShow Answer

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

Correct Answerverified1) The reactants and products reach an e...View AnswerShow Answer

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)

Correct AnswerverifiedShow Answer

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.

Correct AnswerverifiedShow Answer

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

Correct AnswerverifiedShow Answer

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

Correct AnswerverifiedShow Answer

Which statement regarding the carbon cycle is FALSE?

Correct AnswerverifiedShow Answer

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?

Correct AnswerverifiedIn photosynthesis, carbon dioxide and wa...View AnswerShow Answer

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)

Correct AnswerverifiedShow Answer

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

Correct AnswerverifiedShow Answer

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)

Correct AnswerverifiedShow Answer

Correct AnswerverifiedC6 H12 O6 (aq) \(\rightarrow\) 2C2 H5 OH(aq) + 2 CO2 (g), percent yield = 77.1%

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

Correct AnswerverifiedShow Answer

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)

Correct Answer
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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

Correct Answer
verified
Largest: Na₂O.One molecule has two Na ato...
View Answer

Correct Answer
verified
A

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

Correct Answer
verified

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) .

Correct Answer
verified

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)

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

Correct Answer
verified

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

Correct Answer
verified
Formaldehy...
View Answer

Correct Answer
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1) The reactants and products reach an e...
View Answer

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)

Correct Answer
verified

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.

Correct Answer
verified

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

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

Correct Answer
verified

Correct Answer
verified

Correct Answer
verified
In photosynthesis, carbon dioxide and wa...
View Answer

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)

Correct Answer
verified

Correct Answer
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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)

Correct Answer
verified

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

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

Correct Answer
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