Question 1

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

Accepted Answer

All statements A through D are correct regarding photosynthesis. Photosynthesis converts light energy into chemical energy, produces oxygen, consumes atmospheric carbon dioxide, and generates glucose.

Question 2

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 balanced chemical reaction equation best represents the reaction that occurs in this fuel cell?

Accepted Answer

The balanced chemical reaction for the methanol fuel cell is 2CH₃OH + 3O₂ $\rightarrow$ 2CO₂ + 4H₂O, which shows methanol reacting with oxygen to produce carbon dioxide and water.

Question 3

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?

Accepted Answer

The answer of One form of elemental sulfur is a...

Question 4

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

Accepted Answer

We start by balancing the number of oxygen atoms on both sides: O₃ + I^- + H₂O F1F1F1S1F1F1F10 I₂ + OH^- + O₂ 13 + 1 + 12F1F1F1S1 = 12 + 1F1F1F1S1 + 12F1F1F1S1 Simplifying, we get: F1F1F1S1 = 8 So the sum of the stoichiometric coefficients is 8, which corresponds to answer choice C.

Question 5

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?

Accepted Answer

The answer of The combustion of butane (C₄H₁₀) forms carbon...

Question 6

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

Accepted Answer

To balance the equation for the combustion of octane, we first balance the carbons, then the hydrogens, then the oxygens:
C8H18 + O2 -> CO2 + H2O
2C8H18 + 25O2 -> 16CO2 + 18H2O
The coefficients that balance the equation are 2, 25, 16, and 18, so the correct choice is (D).

Question 7

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? Note that the number of molecules of a gas is proportional to the volume of the gas at a given pressure and temperature.

Accepted Answer

The answer of In a demonstration of the complete combustion...

Question 8

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?

Accepted Answer

The balanced chemical equation for the oxidation of glucose (C6H12O6) by molecular oxygen (O2) to produce carbon dioxide (CO2) and water (H2O) is: C6H12O6 + 6O2 -> 6CO2 + 6H2O. Therefore, 6 molecules of O2 are needed for each molecule of glucose.

Question 9

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?

Accepted Answer

The balanced equation for the metabolism of glucose to produce carbon dioxide and water is:

C6H12O6 + 6O2 → 6CO2 + 6H2O

From the equation, we can see that for every molecule of glucose metabolized, 6 molecules of oxygen are consumed to produce 6 molecules of carbon dioxide.

The molecular weight of glucose is 180 g/mol. To calculate the amount of oxygen needed to produce 1 kg of carbon dioxide, we can use the ratio of their molecular weights:

6 mol O2 / 6 mol CO2 = 32 g/mol O2 / 44 g/mol CO2 ≈ 0.73

Therefore, to produce 1 kg of carbon dioxide, 0.73 kg or 730 g of oxygen is needed.

Question 10

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?

Accepted Answer

When one molecule of sulfur dioxide (SO2) reacts with one molecule of water (H2O), the product is one molecule of sulfurous acid (H2SO3).

Question 11

The combustion of fossil fuels is the main anthropogenic source of carbon dioxide in the atmosphere. During the combustion of gasoline in automobile engines, oxygen reacts with hydrocarbons to produce carbon dioxide and water. Assume gasoline is octane (C₈H₁₈). Write the balanced reaction equation, and report the sum of the stoichiometric coefficients written as integers.

Accepted Answer

The answer of The combustion of fossil fuels is the...

Question 12

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?

Accepted Answer

The balanced chemical equation for the reaction between phosphoric acid (H₃PO₄) and calcium hydroxide (Ca(OH)₂) to produce calcium phosphate (Ca₃(PO₄)₂) and water (H₂O) is: 2H₃PO₄ + 3Ca(OH)₂ → Ca₃(PO₄)₂ + 6H₂O. This shows that for each mole of calcium phosphate produced, 6 moles of water are produced.

Question 13

Burning coal that contains sulfur releases sulfur dioxide gas into the atmosphere where it combines with water to form sulfurous and sulfuric acid, thereby producing acid rain. Assume sulfur in coal is in the form of pyrite (FeS₂(s)), which reacts with molecular oxygen to produce Fe₂O₃(s) and SO₂(g). Write the balanced equation for this reaction and report the sum of the stoichiometric coefficients, written as integers.

Accepted Answer

The balanced equation for the reaction between pyrite and molecular oxygen is:

4FeS2(s) + 11O2(g) → 2Fe2O3(s) + 8SO2(g)

The sum of the stoichiometric coefficients is 4 + 11 + 2 + 8 = 25, so the answer is (D).

Question 14

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

Accepted Answer

The answer of Baking soda (NaHCO₃, 84.0 g/mol) requires acids...

Question 15

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.

Accepted Answer

The balanced chemical equation for the combustion of C₁₆H₃₄ can be written as: C₁₆H₃₄ + (117/4)O2 → 116CO2 + (1/2)H2O + 134/2SO2 The sum of the stoichiometric coefficients is 116+117/4+1/2+134/2 = 292/4+1/2 = 117. Therefore, the best choice is E.

Question 16

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

Accepted Answer

The balanced equation for the combustion of butane is 2C4H10 + 13O2 → 8CO2 + 10H2O, so the coefficients for oxygen and water are 13 and 10, respectively.

Question 17

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?

Accepted Answer

The balanced chemical equation for the combustion of ethanol is: C2H5OH + 3O2 → 2CO2 + 3H2O. From this, 1 mole of ethanol (46.1 g) produces 2 moles of CO2. The molar mass of CO2 is 44.0 g/mol, so 2 moles of CO2 weigh 88.0 g.

Question 18

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?

Accepted Answer

The combustion of fossil fuels produces carbon dioxide (CO2) and water (H2O). The balanced chemical equation for the combustion of methane (CH4), a typical fossil fuel, is:CH4 + 2O2 → CO2 + 2H2OFrom the balanced chemical equation, we can see that 1 mole of methane requires 2 moles of oxygen to produce 1 mole of carbon dioxide. The molar mass of carbon is 12 g/mol, and the molar mass of oxygen is 16 g/mol. Therefore, 12 kg of carbon requires 32 kg of oxygen to produce 44 kg of carbon dioxide.Given that the combustion of fossil fuels adds about 5 * 10^12 kg of carbon to the atmosphere as CO2 each year, we can calculate the amount of oxygen required as follows:Amount of oxygen required = (5 * 10^12 kg C) * (32 kg O2 / 12 kg C) = 1.3 * 10^13 kg O2Therefore, the correct answer is B) about 1.3 * 10^13 kg.

Question 19

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

Accepted Answer

All statements A through D are correct regarding the carbon cycle. Petroleum and coal are carbon sediments, respiration does produce CO2, water is indeed a reactant in photosynthesis, and forest fires contribute to the carbon cycle by releasing stored carbon.

Question 20

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)

Accepted Answer

From the balanced equation, it can be seen that 1 mole of copper sulfate reacts with 1 mole of zinc. The given amount of copper sulfate is 454 g, which is equal to 2.84 moles (454 g / 160 g/mol). Therefore, 2.84 moles of zinc is required to react with this amount of copper sulfate. This is equal to 171.5 g of zinc (2.84 moles x 63.5 g/mol). However, the question is asking for the mass of zinc that would react, which is different from the amount required. From the equation, it can be seen that 1 mole of zinc produces 1 mole of copper. Therefore, the amount of zinc that would react is also 2.84 moles, which is equal to 180.2 g (2.84 moles x 63.5 g/mol). However, this is the amount of zinc that is consumed in the reaction. To find the amount of zinc that actually reacts to form copper, we need to find the amount of copper that is produced. From the equation, it can be seen that 1 mole of zinc produces 1 mole of copper. Therefore, the amount of copper produced is also 2.84 moles, which is equal to 454 g (2.84 moles x 160 g/mol). Therefore, the correct answer is B) 186 g, which is the amount of zinc that reacts with the copper sulfate to form 186 g of copper.

Quiz 3: Stoichiometry: Mass, Formulas, and Reactions

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

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?

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

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?

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

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?

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?

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?

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?

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.

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

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?

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?

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

Quiz 3: Stoichiometry: Mass, Formulas, and Reactions

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

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?

Ozone (O3) reacts with iodide (I-) and water to form iodine (I2) , hydroxide (OH-) , and oxygen (O2) . Balance the following reaction equation and report the sum of the stoichiometric coefficients. O3 + I- + H2O →\rightarrow→ I2 + OH- + O2

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?

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

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?

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?

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?

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?

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.

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

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?

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?

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

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

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?

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

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?

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?

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?

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?

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.

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

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?

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?