Question 1

Balance the following equation: UO2(s) + HF(l) → UF4(s) + H2O(l)

Accepted Answer

A)  UO2(s) + 2HF(l) → UF4(s) + H2O(l) 
B)  UO2(s) + 4HF(l) → UF4(s) + 2H2O(l) 
C)  UO2(s) + H4F4(l) → UF4(s) + H4O2(l) 
D)  UO2(s) + 4HF(l) → UF4(s) + 4H2O(l) 
E)  UO2(s) + 8HF(l) → 2UF4(s) + 4H2O(l) F) A) and B)
G) All of the above

Question 2

What is the coefficient of O2 when the following equation is properly balanced with the smallest set of whole numbers? ___ CH3OH + ___ O2 → ___ CO2 + ___ H2O

Accepted Answer

A)  1
B)  2
C)  3
D)  7
E)  None of these answers is correct.F) D) and E)
G) B) and D)

Question 3

How many grams of calcium metal is required to react with 7.75 g water to produce calcium hydroxide and hydrogen gas?

Accepted Answer

A)  8.62 g
B)  34.5 g
C)  4.31 g
D)  40.1 g
E)  17.2 gF) A) and B)
G) B) and E)

Question 4

What mass of sodium fluoride (used in water fluoridation and the manufacture of insecticides) is required to form 485 g of sulfur tetrafluoride? 3SCl2(l) + 4NaF(s) → SF4(g) + S2Cl2(l) + 4NaCl(s)

Accepted Answer

A)  1.94 kg
B)  1.51 kg
C)  754 g
D)  205 g
E)  51.3 gF) B) and E)
G) B) and C)

Question 5

If 13.9 g of oxygen react with 33.7 g of calcium to produce calcium oxide,what is the limiting reactant and what mass of calcium oxide is produced?

Accepted Answer

A)  Calcium is the limiting reactant and 47.2 g of calcium oxide are produced
B)  Oxygen is the limiting reactant and 24.4 g of calcium oxide are produced
C)  Calcium is the limiting reactant and 47.20 g of calcium oxide are produced
D)  Oxygen is the limiting reactant and 48.7 g of calcium oxide are produced
E)  Calcium is the limiting reactant and 23.6 g of calcium oxide are producedF) C) and D)
G) B) and C)

Question 6

What is the coefficient of H2O when the following equation is properly balanced with the smallest set of whole numbers? ___ Na + ___ H2O → ___ NaOH + ___ H2

Accepted Answer

A)  1
B)  2
C)  3
D)  4
E)  5F) B) and E)
G) A) and E)

Question 7

Methanol (CH3OH) is converted to bromomethane (CH3Br) as follows: CH3OH + HBr → CH3Br + H2O
If 12.23 g of bromomethane are produced when 5.00 g of methanol is reacted with excess HBr,what is the percentage yield?

Accepted Answer

A)  12.9%
B)  33.8%
C)  40.9%
D)  59.1%
E)  82.6%F) D) and E)
G) B) and D)

Question 8

A compound containing chromium and silicon contains 73.52 mass percent chromium.Determine its empirical formula.

Accepted Answer

A)  CrSi3
B)  Cr2Si3
C)  Cr3Si
D)  Cr3Si2
E)  Cr4Si3F) D) and E)
G) C) and E)

Question 9

Hydroxyl ammonium nitrate contains 29.17 mass % N,4.20 mass % H,and 66.63 mass % O.If its molar mass is between 94 and 98 g/mol,what is its molecular formula?

Accepted Answer

A)  NH2O5
B)  N2H4O4
C)  N3H3O3
D)  N4H8O2
E)  N2H2O4F) D) and E)
G) B) and C)

Question 10

What is the empirical formula for a sample containing 81.70% carbon and 18.29% hydrogen?

Accepted Answer

A)  CH
B)  CH3
C)  C2H6
D)  CH4
E)  C3H8F) C) and E)
G) None of the above

Question 11

Tetraphosphorus hexaoxide is formed by the reaction of phosphorus with oxygen gas.If a mixture of 75.3 g of phosphorus and 38.7 g of oxygen produce 43.3 g of P4O6,what is the percent yield for the reaction?

Accepted Answer

A)  57.5%
B)  48.8%
C)  38.0%
D)  89.4%
E)  16.3%F) C) and D)
G) B) and C)

Question 12

If 119.3 g of PCl5 are formed from the reaction of 61.3 g Cl2 with excess PCl3,what is the percent yield? PCl3(g) + Cl2(g) → PCl5(g)

Accepted Answer

A)  94.6%
B)  66.3%
C)  57.3%
D)  51.3%
E)  48.6%F) A) and C)
G) A) and B)

Question 13

The ______________ is defined by the following equation

Accepted Answer

The answer of The ______________ is defined by the following...

Question 14

The density of water is 1.00 g/mL at 4°C.How many water molecules are present in 6.25 mL of water at this temperature? (NA = 6.022 × 1023 mol-1)

Accepted Answer

A)  6.27 × 1023 molecules
B)  3.76 × 1024 molecules
C)  2.09 × 1023 molecules
D)  6.02 × 1023 molecules
E)  0.347 moleculesF) C) and D)
G) C) and E)

Question 15

Calculate the molecular mass of tetraphosphorus decaoxide,P4O10,a corrosive substance which can be used as a drying agent.

Accepted Answer

A)  469.73 amu
B)  283.88 amu
C)  190.97 amu
D)  139.88 amu
E)  94.97 amuF) B) and E)
G) A) and B)

Question 16

There is only one distinct empirical formula for each compound that exists.

Accepted Answer

A) True 
 B)False

Question 17

What mass of Cr can be produced by the reaction of 44.1 g of Cr2O3 with 35.0 g of Al according to the following chemical equation? 2Al + Cr2O3 → Al2O3 + 2Cr

Accepted Answer

A)  15.1 g
B)  30.2 g
C)  67.4 g
D)  99.9 g
E)  104 gF) C) and D)
G) A) and B)

Question 18

Household sugar,sucrose,has the molecular formula C12H22O11.What is the % of carbon in sucrose,by mass?

Accepted Answer

A)  26.7%
B)  33.3%
C)  41.4%
D)  42.1%
E)  51.4%F) None of the above
G) D) and E)

Question 19

How many moles of ammonia,NH3,are in 13.81 g of NH3?

Accepted Answer

A)  1.234 moles
B)  0.8107 moles
C)  8.316 × 1024 moles
D)  4.881 × 1023 moles
E)  235.3 molesF) A) and D)
G) A) and C)

Question 20

Balance the following equation: C8H18O3(l) + O2(g) → H2O(g) + CO2(g)

Accepted Answer

A)  C8H18O3(l) + 8O2(g) → 9H2O(g) + 8CO2(g) 
B)  C8H18O3(l) + 11O2(g) → 9H2O(g) + 8CO2(g) 
C)  2C8H18O3(l) + 22O2(g) → 9H2O(g) + 16CO2(g) 
D)  C8H18O3(l) + 13O2(g) → 18H2O(g) + 8CO2(g) 
E)  2C8H18O3(l) + 17O2(g) → 18H2O(g) + 16CO2(g) F) A) and B)
G) All of the above

Exam 3: Stoichiometry Ratios of Combination

If 119.3 g of PCl5 are formed from the reaction of 61.3 g Cl2 with excess PCl3,what is the percent yield? PCl3(g) + Cl2(g) → PCl5(g)

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Calculate the molecular mass of tetraphosphorus decaoxide,P4O10,a corrosive substance which can be used as a drying agent.

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Tetraphosphorus hexaoxide is formed by the reaction of phosphorus with oxygen gas.If a mixture of 75.3 g of phosphorus and 38.7 g of oxygen produce 43.3 g of P4O6,what is the percent yield for the reaction?

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Balance the following equation: C8H18O3(l) + O2(g) → H2O(g) + CO2(g)

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There is only one distinct empirical formula for each compound that exists.

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What mass of sodium fluoride (used in water fluoridation and the manufacture of insecticides) is required to form 485 g of sulfur tetrafluoride? 3SCl2(l) + 4NaF(s) → SF4(g) + S2Cl2(l) + 4NaCl(s)

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Methanol (CH3OH) is converted to bromomethane (CH3Br) as follows: CH3OH + HBr → CH3Br + H2O If 12.23 g of bromomethane are produced when 5.00 g of methanol is reacted with excess HBr,what is the percentage yield?

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Household sugar,sucrose,has the molecular formula C12H22O11.What is the % of carbon in sucrose,by mass?

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Hydroxyl ammonium nitrate contains 29.17 mass % N,4.20 mass % H,and 66.63 mass % O.If its molar mass is between 94 and 98 g/mol,what is its molecular formula?

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What is the coefficient of O2 when the following equation is properly balanced with the smallest set of whole numbers? ___ CH3OH + ___ O2 → ___ CO2 + ___ H2O

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Balance the following equation: UO2(s) + HF(l) → UF4(s) + H2O(l)

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What is the coefficient of H2O when the following equation is properly balanced with the smallest set of whole numbers? ___ Na + ___ H2O → ___ NaOH + ___ H2

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How many moles of ammonia,NH3,are in 13.81 g of NH3?

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If 13.9 g of oxygen react with 33.7 g of calcium to produce calcium oxide,what is the limiting reactant and what mass of calcium oxide is produced?

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The ______________ is defined by the following equation

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What mass of Cr can be produced by the reaction of 44.1 g of Cr2O3 with 35.0 g of Al according to the following chemical equation? 2Al + Cr2O3 → Al2O3 + 2Cr

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What is the empirical formula for a sample containing 81.70% carbon and 18.29% hydrogen?

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A compound containing chromium and silicon contains 73.52 mass percent chromium.Determine its empirical formula.

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How many grams of calcium metal is required to react with 7.75 g water to produce calcium hydroxide and hydrogen gas?

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The density of water is 1.00 g/mL at 4°C.How many water molecules are present in 6.25 mL of water at this temperature? (NA = 6.022 × 1023 mol-1)

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If 119.3 g of PCl₅ are formed from the reaction of 61.3 g Cl₂ with excess PCl₃,what is the percent yield? PCl₃(g) + Cl₂(g) → PCl₅(g)

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Calculate the molecular mass of tetraphosphorus decaoxide,P₄O₁₀,a corrosive substance which can be used as a drying agent.

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Tetraphosphorus hexaoxide is formed by the reaction of phosphorus with oxygen gas.If a mixture of 75.3 g of phosphorus and 38.7 g of oxygen produce 43.3 g of P₄O₆,what is the percent yield for the reaction?

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Balance the following equation: C₈H₁₈O₃(l) + O₂(g) → H₂O(g) + CO₂(g)

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What mass of sodium fluoride (used in water fluoridation and the manufacture of insecticides) is required to form 485 g of sulfur tetrafluoride? 3SCl₂(l) + 4NaF(s) → SF₄(g) + S₂Cl₂(l) + 4NaCl(s)

Correct Answer
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Methanol (CH₃OH) is converted to bromomethane (CH₃Br) as follows: CH₃OH + HBr → CH₃Br + H₂O If 12.23 g of bromomethane are produced when 5.00 g of methanol is reacted with excess HBr,what is the percentage yield?

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Household sugar,sucrose,has the molecular formula C₁₂H₂₂O₁₁.What is the % of carbon in sucrose,by mass?

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What is the coefficient of O2 when the following equation is properly balanced with the smallest set of whole numbers? _ CH₃OH + _ O₂ → _ CO₂ + _ H₂O

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Balance the following equation: UO₂(s) + HF(l) → UF₄(s) + H₂O(l)

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What is the coefficient of H2O when the following equation is properly balanced with the smallest set of whole numbers? _ Na + _ H₂O → _ NaOH + _ H₂

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How many moles of ammonia,NH₃,are in 13.81 g of NH₃?

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What mass of Cr can be produced by the reaction of 44.1 g of Cr₂O₃ with 35.0 g of Al according to the following chemical equation? 2Al + Cr₂O₃ → Al₂O₃ + 2Cr

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The density of water is 1.00 g/mL at 4°C.How many water molecules are present in 6.25 mL of water at this temperature? (N_A = 6.022 × 10²³ mol-1)

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