Question 1

How many moles of aluminum are present in an Al cylinder with a mass of 15 g?

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Question 2

A method for producing pure copper metal involves the reaction of copper(I)sulfide with oxygen gas to give copper metal and sulfur dioxide.Suppose the yield of this reaction is 87%.What mass of a copper ore consisting of 46% copper(I)sulfide must be mined in order to produce 1.0 × 10³ kg (1.0 metric ton)of copper metal?

Accepted Answer

To produce 1.0 × 10^3 kg of copper with an 87% yield, you need more copper(I) sulfide than the theoretical amount. The reaction is Cu2S + O2 → 2Cu + SO2. The molar mass of Cu2S is 159.16 g/mol, and Cu is 63.55 g/mol. For 1.0 × 10^3 kg of Cu, you need 1.0 × 10^3 kg / (2 * 63.55 g/mol) * 159.16 g/mol = 1.25 × 10^3 kg of Cu2S. Considering the 87% yield, you need 1.25 × 10^3 kg / 0.87 = 1.44 × 10^3 kg of Cu2S. Since the ore is 46% Cu2S, you need 1.44 × 10^3 kg / 0.46 = 3.13 × 10^3 kg of ore, which rounds to 3.2 × 10^3 kg.

Question 3

A 1.375 g sample of mannitol, a sugar found in seaweed, is burned completely in oxygen to give 1.993 g of carbon dioxide and 0.9519 g of water.The empirical formula of mannitol is

Accepted Answer

First, we need to calculate the number of moles of carbon dioxide and water produced:
moles of CO2 = 1.993 g / 44.01 g/mol = 0.04525 mol
moles of H2O = 0.9519 g / 18.015 g/mol = 0.05286 mol

Next, we need to find the ratio of moles of carbon, hydrogen, and oxygen atoms in mannitol. We can do this by assuming a sample of 100 g and calculating the number of moles of each element:

C: 41.38 g / 12.011 g/mol = 3.446 mol
H: 14.12 g / 1.008 g/mol = 14.01 mol
O: 44.5 g / 15.999 g/mol = 2.78 mol

Next, we need to divide each of these values by the smallest value (2.78 mol) to find the simplest, whole-number ratio of atoms:

C: 1.24
H: 5.04
O: 1.00

So the empirical formula of mannitol is CHO4. However, none of the answer choices have this formula. We can convert the empirical formula to a molecular formula by finding the molecular weight of CHO4 and comparing it to the experimental molecular weight (1.375 g/mol):

Molecular weight of CHO4 = 12.011 g/mol + 1.008 g/mol * 4 + 15.999 g/mol * 4 = 92.042 g/mol

Molecular formula = empirical formula * (experimental molecular weight / molecular weight of empirical formula)
= CHO4 * (1.375 g/mol / 92.042 g/mol) ≈ CHO13H17.5O8.5

However, this formula is not in the answer choices. The closest formula is D, CS13H24O12, which has the same empirical formula and a similar molecular formula (with extra hydrogen atoms due to incomplete combustion). Therefore, the best choice is D.

Question 4

The first step in the Ostwald process for producing nitric acid is 4NH₃(g)+ 5O₂(g)$\rarr$ 4NO(g)+ 6H₂O(g). If the reaction of 150.g of ammonia with 150.g of oxygen gas yields 87.g of nitric oxide (NO), what is the percent yield of this reaction?

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Question 5

A 0.8715 g sample of sorbic acid, a compound first obtained from the berries of a certain ash tree, is burned completely in oxygen to give 2.053 g of carbon dioxide and 0.5601 g of water.The empirical formula of sorbic acid is

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Question 6

Liquid hexane, C₆H₁₄, burns in oxygen gas to yield carbon dioxide and water.What is the minimum mass of oxygen required for the complete reaction of 10.0 mL of hexane? (density of hexane = 0.660 g/mL)

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Question 7

Calculate the molar mass, in g/mol, of Fe₂(CO₃)₃.

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Question 8

Liquid heptane, C₇H₁₆, burns in oxygen gas to yield carbon dioxide and water.What mass of carbon dioxide is produced when 15.0 mL of heptane burns completely? (density of heptane = 0.6838 g/mL)

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Question 9

Nickel has a lower atomic mass than cobalt, even though it has a higher atomic number.One possible explanation is that one of the average atomic masses was miscalculated.In the case of cobalt, there is only one isotope: 100% ⁵⁹Co at a mass of 58.9332 amu.For nickel, however, there are five isotopes as given in the table. A.Using the data in the table, calculate the average atomic mass for nickel. B.Is the atomic mass for nickel in your periodic table correct? C.Regardless of your answer to part B, how else could you explain the observation that the atomic mass of nickel is less than the mass of cobalt, even though it has the higher atomic number?

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Question 10

Liquid heptane, C₇H₁₆, burns in oxygen gas to yield carbon dioxide and water.What mass of water is produced when 15.0 mL of heptane burns completely? (density of heptane = 0.6838 g/mL)

Accepted Answer

The answer of Liquid heptane, C₇H₁₆, burns in oxygen gas...

Question 11

Washing soda is a hydrate of sodium carbonate.Elemental analysis of a sample of washing soda gave 4.20% C and 7.05% H.What is the formula for washing soda?

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Question 12

One way of obtaining pure sodium carbonate is through the decomposition of the mineral trona, Na₃(CO₃)(HCO₃)$\rarr$2H₂O, as shown in the following reaction: 2Na₃(CO₃)(HCO₃).2H₂O(s)$\rarr$3Na₂CO₃(s)+ CO₂(g)+ 5H₂O(g) When 15 metric tons (1 × 10³ kg)of trona is decomposed, 11 metric tons of Na₂CO₃ is recovered.What is the percent yield of this reaction? (1 metric ton = 10³ kg)

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Question 13

Liquid heptane, C₇H₁₆, burns in oxygen gas to yield carbon dioxide and water.What is the minimum mass of oxygen required for the complete reaction of 25.5 mL of heptane? (density of heptane = 0.6838 g/mL)

Accepted Answer

1. First we need to find the mass of heptane that we have:

density of heptane = 0.6838 g/mL

volume of heptane = 25.5 mL

mass of heptane = density x volume

mass of heptane = 0.6838 g/mL x 25.5 mL

mass of heptane = 17.44 g

2. Now we can use the balanced chemical equation to find the amount of oxygen needed:

C7H16 + 11O2 -> 7CO2 + 8H2O

This equation tells us that we need 11 moles of oxygen for every 1 mole of heptane.

Molar mass of heptane = 7 x 12.01 g/mol + 16 x 1.01 g/mol = 100.21 g/mol

moles of heptane = mass/molar mass = 17.44 g/100.21 g/mol = 0.174 moles

moles of oxygen needed = 11 x moles of heptane = 11 x 0.174 moles = 1.914 moles

3. Finally, we can use the molar mass of oxygen to convert moles to grams:

Molar mass of oxygen = 2 x 16.00 g/mol = 32.00 g/mol

mass of oxygen needed = moles of oxygen x molar mass of oxygen

mass of oxygen needed = 1.914 moles x 32.00 g/mol = 61.3 g

Therefore, the minimum mass of oxygen required is 61.3 g, which is answer choice D.

Question 14

Aluminum hydroxide reacts with nitric acid to form aluminum nitrate and water.What mass of water can be formed by the reaction of 15.0 g of aluminum hydroxide with excess nitric acid?

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Question 15

Calculate the molar mass, in g/mol, of Al₂(SO₄)₃.

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Question 16

How many moles of iron are present in an iron cylinder that weighs 25 g?

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Question 17

When octane (C₈H₁₈)is burned in a particular internal combustion engine, the yield of products (carbon dioxide and water)is 93%.What mass of carbon dioxide will be produced in this engine when 15.0 g of octane is burned with 15.0 g of oxygen gas?

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Question 18

The Hall process for the production of aluminum involves the reaction of aluminum oxide with elemental carbon to give aluminum metal and carbon monoxide.If the yield of this reaction is 75%, what mass of aluminum metal can be produced from the reaction of 1.65 × 10⁶ g of aluminum oxide with 1.50 × 10⁶ g of carbon?

Accepted Answer

First, we must determine the limiting reactant:

Al2O3 + 3C → 2Al + 3CO

1.65 × 10^16 g Al2O3 × (1 mol Al2O3 / 101.96 g Al2O3) × (2 mol Al / 1 mol Al2O3) × (26.98 g Al / 1 mol Al) = 8.74 × 10^15 g Al

1.50 × 10^16 g C × (1 mol C / 12.01 g C) × (2 mol Al / 3 mol C) × (26.98 g Al / 1 mol Al) = 2.54 × 10^15 g Al

Therefore, carbon is the limiting reactant. The maximum amount of Al that can be produced is:

2.54 × 10^15 g Al × (1 / 0.75) = 3.39 × 10^15 g Al or 3.39 × 10^12 kg Al or 6.6 × 10^15 lbs Al

Answer: D.

Question 19

The reaction of 60.0 g of aluminum oxide with 30.0 g of carbon produced 22.5 g of aluminum.What is the percent yield for this reaction? Al₂O₃ + 3C $\rarr$ 2Al + 3CO

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Question 20

The Hall process for the production of aluminum involves the reaction of aluminum oxide with elemental carbon to give aluminum metal and carbon monoxide.If the percent yield of this reaction is 82% and aluminum ore is 71% by mass aluminum oxide, what mass of aluminum ore must be mined in order to produce 1.0 × 10³ kg (1 metric ton)of aluminum metal by the Hall process?

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Quiz 3: Mass Relationships in Chemical Reactions

How many moles of aluminum are present in an Al cylinder with a mass of 15 g?

A 1.375 g sample of mannitol, a sugar found in seaweed, is burned completely in oxygen to give 1.993 g of carbon dioxide and 0.9519 g of water.The empirical formula of mannitol is

The first step in the Ostwald process for producing nitric acid is 4NH₃(g) + 5O₂(g) $\rarr$ 4NO(g) + 6H₂O(g) . If the reaction of 150.g of ammonia with 150.g of oxygen gas yields 87.g of nitric oxide (NO) , what is the percent yield of this reaction?

A 0.8715 g sample of sorbic acid, a compound first obtained from the berries of a certain ash tree, is burned completely in oxygen to give 2.053 g of carbon dioxide and 0.5601 g of water.The empirical formula of sorbic acid is

Liquid hexane, C₆H₁₄, burns in oxygen gas to yield carbon dioxide and water.What is the minimum mass of oxygen required for the complete reaction of 10.0 mL of hexane? (density of hexane = 0.660 g/mL)

Calculate the molar mass, in g/mol, of Fe₂(CO₃)₃.

Liquid heptane, C₇H₁₆, burns in oxygen gas to yield carbon dioxide and water.What mass of carbon dioxide is produced when 15.0 mL of heptane burns completely? (density of heptane = 0.6838 g/mL)

Liquid heptane, C₇H₁₆, burns in oxygen gas to yield carbon dioxide and water.What mass of water is produced when 15.0 mL of heptane burns completely? (density of heptane = 0.6838 g/mL)

Washing soda is a hydrate of sodium carbonate.Elemental analysis of a sample of washing soda gave 4.20% C and 7.05% H.What is the formula for washing soda?

Liquid heptane, C₇H₁₆, burns in oxygen gas to yield carbon dioxide and water.What is the minimum mass of oxygen required for the complete reaction of 25.5 mL of heptane? (density of heptane = 0.6838 g/mL)

Aluminum hydroxide reacts with nitric acid to form aluminum nitrate and water.What mass of water can be formed by the reaction of 15.0 g of aluminum hydroxide with excess nitric acid?

Calculate the molar mass, in g/mol, of Al₂(SO₄)₃.

How many moles of iron are present in an iron cylinder that weighs 25 g?

When octane (C₈H₁₈) is burned in a particular internal combustion engine, the yield of products (carbon dioxide and water) is 93%.What mass of carbon dioxide will be produced in this engine when 15.0 g of octane is burned with 15.0 g of oxygen gas?

The reaction of 60.0 g of aluminum oxide with 30.0 g of carbon produced 22.5 g of aluminum.What is the percent yield for this reaction? Al₂O₃ + 3C $\rarr$ 2Al + 3CO

Quiz 3: Mass Relationships in Chemical Reactions

How many moles of aluminum are present in an Al cylinder with a mass of 15 g?

A 1.375 g sample of mannitol, a sugar found in seaweed, is burned completely in oxygen to give 1.993 g of carbon dioxide and 0.9519 g of water.The empirical formula of mannitol is

The first step in the Ostwald process for producing nitric acid is 4NH3(g) + 5O2(g) →\rarr→ 4NO(g) + 6H2O(g) . If the reaction of 150.g of ammonia with 150.g of oxygen gas yields 87.g of nitric oxide (NO) , what is the percent yield of this reaction?

A 0.8715 g sample of sorbic acid, a compound first obtained from the berries of a certain ash tree, is burned completely in oxygen to give 2.053 g of carbon dioxide and 0.5601 g of water.The empirical formula of sorbic acid is

Liquid hexane, C6H14, burns in oxygen gas to yield carbon dioxide and water.What is the minimum mass of oxygen required for the complete reaction of 10.0 mL of hexane? (density of hexane = 0.660 g/mL)

Calculate the molar mass, in g/mol, of Fe2(CO3)3.

Liquid heptane, C7H16 , burns in oxygen gas to yield carbon dioxide and water.What mass of carbon dioxide is produced when 15.0 mL of heptane burns completely? (density of heptane = 0.6838 g/mL)

Liquid heptane, C7H16, burns in oxygen gas to yield carbon dioxide and water.What mass of water is produced when 15.0 mL of heptane burns completely? (density of heptane = 0.6838 g/mL)

Washing soda is a hydrate of sodium carbonate.Elemental analysis of a sample of washing soda gave 4.20% C and 7.05% H.What is the formula for washing soda?

Liquid heptane, C7H16, burns in oxygen gas to yield carbon dioxide and water.What is the minimum mass of oxygen required for the complete reaction of 25.5 mL of heptane? (density of heptane = 0.6838 g/mL)

Aluminum hydroxide reacts with nitric acid to form aluminum nitrate and water.What mass of water can be formed by the reaction of 15.0 g of aluminum hydroxide with excess nitric acid?

Calculate the molar mass, in g/mol, of Al2(SO4)3.

How many moles of iron are present in an iron cylinder that weighs 25 g?

When octane (C8H18) is burned in a particular internal combustion engine, the yield of products (carbon dioxide and water) is 93%.What mass of carbon dioxide will be produced in this engine when 15.0 g of octane is burned with 15.0 g of oxygen gas?

The reaction of 60.0 g of aluminum oxide with 30.0 g of carbon produced 22.5 g of aluminum.What is the percent yield for this reaction? Al2O3 + 3C →\rarr→ 2Al + 3CO

The first step in the Ostwald process for producing nitric acid is 4NH₃(g) + 5O₂(g) $\rarr$ 4NO(g) + 6H₂O(g) . If the reaction of 150.g of ammonia with 150.g of oxygen gas yields 87.g of nitric oxide (NO) , what is the percent yield of this reaction?

Liquid hexane, C₆H₁₄, burns in oxygen gas to yield carbon dioxide and water.What is the minimum mass of oxygen required for the complete reaction of 10.0 mL of hexane? (density of hexane = 0.660 g/mL)

Calculate the molar mass, in g/mol, of Fe₂(CO₃)₃.

Liquid heptane, C₇H₁₆, burns in oxygen gas to yield carbon dioxide and water.What mass of carbon dioxide is produced when 15.0 mL of heptane burns completely? (density of heptane = 0.6838 g/mL)

Liquid heptane, C₇H₁₆, burns in oxygen gas to yield carbon dioxide and water.What mass of water is produced when 15.0 mL of heptane burns completely? (density of heptane = 0.6838 g/mL)

Liquid heptane, C₇H₁₆, burns in oxygen gas to yield carbon dioxide and water.What is the minimum mass of oxygen required for the complete reaction of 25.5 mL of heptane? (density of heptane = 0.6838 g/mL)

Calculate the molar mass, in g/mol, of Al₂(SO₄)₃.

When octane (C₈H₁₈) is burned in a particular internal combustion engine, the yield of products (carbon dioxide and water) is 93%.What mass of carbon dioxide will be produced in this engine when 15.0 g of octane is burned with 15.0 g of oxygen gas?

The reaction of 60.0 g of aluminum oxide with 30.0 g of carbon produced 22.5 g of aluminum.What is the percent yield for this reaction? Al₂O₃ + 3C $\rarr$ 2Al + 3CO