Question 1

A carton of low-fat yogurt says it has 1.70 x 102 Calories. What is the equivalent amount of energy in units of joules?

Accepted Answer

A) 711 J 
B) 7.11 x 105 J 
C) 4.06 x 104 J 
D) 406 J 
E) 40.6 J 
A) 711 J 
B) 7.11 x 105 J 
C) 4.06 x 104 J 
D) 406 J 
E) 40.6 J

Question 2

In the process of obtaining lead from PbS, or galena, the galena is "roasted" (heated in the presence of oxygen), so that the following reaction occurs: 2PbS(s)+ 3O2(g)→ 2PbO(s)+ 2SO2(g)If 35.2 g of PbS is mixed with 15.5 g of oxygen, how many grams of PbO should form?

Accepted Answer

A) 32.8 g 
B) 72.1 g 
C) 105 g 
D) 65.7 g 
E) 49.2 g 
A) 32.8 g 
B) 72.1 g 
C) 105 g 
D) 65.7 g 
E) 49.2 g

Question 3

Consider the reaction between hydrogen and oxygen gases to form water: 2H2(g)+ O2(g)→ 2H2O(l)If 8.5 moles of oxygen react with sufficient hydrogen, how many grams of water should form?

Accepted Answer

A) 0.94 g 
B) 0.47 g 
C) .76 g 
D) 3.1 x 102 g 
E) 1.5 x 102 g 
A) 0.94 g 
B) 0.47 g 
C) .76 g 
D) 3.1 x 102 g 
E) 1.5 x 102 g

Question 4

When a substance cools from a high temperature to a low temperature, its heat change value will have a negative sign.

Accepted Answer

A) True 
 B)False

Question 5

Which of the following is the best (simplest)balanced equation to represent the chemical reaction shown in the figure on any scale?

Accepted Answer

A) 16H + 10O → 16H + 10O 
B) 16H + 10O → 8H2O + O2 
C) 8H2 + 5O2 → 8H2O + O2 
D) 2H2 + O2 → 2H2O 
E) 4H2 + 2O2 → 4H2O 
A) 16H + 10O → 16H + 10O 
B) 16H + 10O → 8H2O + O2 
C) 8H2 + 5O2 → 8H2O + O2 
D) 2H2 + O2 → 2H2O 
E) 4H2 + 2O2 → 4H2O

Question 6

When acetylene, C2H2, a fuel used in welding, is burned in air, two molecules of acetylene combine with five oxygen molecules to form four CO2 molecules and two H2O molecules. Select the statement below that is incorrect in regard to this reaction.

Accepted Answer

A) The balanced equation for the reaction is 2C2H2 + 5O2 → 4CO2 + 2H2O. 
B) If 8 acetylene molecules react, 12 CO2 molecules should form. 
C) If 12 H2O molecules are formed, then 30 O2 molecules must have reacted. 
D) If 12 CO2 molecules are formed, then 6 H2O molecules should also form. 
E) If 24 ethanol molecules react, then 60 oxygen molecules must also react 
A) The balanced equation for the reaction is 2C2H2 + 5O2 → 4CO2 + 2H2O. 
B) If 8 acetylene molecules react, 12 CO2 molecules should form. 
C) If 12 H2O molecules are formed, then 30 O2 molecules must have reacted. 
D) If 12 CO2 molecules are formed, then 6 H2O molecules should also form. 
E) If 24 ethanol molecules react, then 60 oxygen molecules must also react

Question 7

A 5.00 g sample of a brownie was burned in a bomb calorimeter containing 2025 g of water. The temperature of the water increased from 23.50°C to 33.47°C. How much heat, in joules, did the brownie release when it burned? [Cwater = 4.184 J/(g°C)]

Accepted Answer

A) 1.99 x 105 J 
B) 2.80 x 105 J 
C) 4.92 x 102 J 
D) 8.45 x 104 J 
E) 7.00 x 102 J 
A) 1.99 x 105 J 
B) 2.80 x 105 J 
C) 4.92 x 102 J 
D) 8.45 x 104 J 
E) 7.00 x 102 J

Question 8

The number of moles of reactant molecules must always equal the number of moles of product molecules in a balanced equation.

Accepted Answer

A) True 
 B)False

Question 9

When the mixture of molecules shown in the molecular-level image undergoes complete reaction, all of these molecules are converted to products. Which of the following reactions could this represent?

Accepted Answer

A) 2N2 + 3O2 → 2N2O3 
B) N2 + 2Cl2 → N2Cl4 
C) O2 + 2H2 → 2H2O 
D) N2 + 3Cl2 → 2NCl3 
E) 3N2 + 2H2 → 3N2H4 
A) 2N2 + 3O2 → 2N2O3 
B) N2 + 2Cl2 → N2Cl4 
C) O2 + 2H2 → 2H2O 
D) N2 + 3Cl2 → 2NCl3 
E) 3N2 + 2H2 → 3N2H4

Question 10

Which of the following is an exothermic process?

Accepted Answer

A) ice melting 
B) water evaporating 
C) boiling soup 
D) condensation of water vapor 
E) Ammonium thiocyanate and barium hydroxide are mixed, resulting in a decrease in temperature of the surroundings 
A) ice melting 
B) water evaporating 
C) boiling soup 
D) condensation of water vapor 
E) Ammonium thiocyanate and barium hydroxide are mixed, resulting in a decrease in temperature of the surroundings

Question 11

Iron metal reacts with hydrochloric acid as follows: 2Fe(s)+ 6HCl(aq)→ 2FeCl3(aq)+ 3H2(g)If 22.4 g of iron react with excess HCl, and 59.4 g of FeCl3 are collected, what is the percent yield of Al2(SO4)3?

Accepted Answer

A) 65.0% 
B) 109% 
C) 91.4% 
D) 73.0% 
E) not enough information given 
A) 65.0% 
B) 109% 
C) 91.4% 
D) 73.0% 
E) not enough information given

Question 12

Which of the following best describes an exothermic reaction?

Accepted Answer

A) Heat must be added to get the reaction to go 
B) The temperature of the surroundings decreases 
C) The potential energy of the reactants is greater than that of the surroundings 
D) Matter is converted into energy 
E) Heat is absorbed by the reaction from the surroundings 
A) Heat must be added to get the reaction to go 
B) The temperature of the surroundings decreases 
C) The potential energy of the reactants is greater than that of the surroundings 
D) Matter is converted into energy 
E) Heat is absorbed by the reaction from the surroundings

Question 13

Which of the following is the best (simplest)balanced equation to represent the chemical reaction shown in the figure on any scale?

Accepted Answer

A) 4A + 8B → 12AB 
B) 2A2 + 4B2 → 4A2B 
C) 2A2 + 4B2 → 4AB2 
D) A2 + B2 → AB2 
E) A2 + 2B2 → 2AB2 
A) 4A + 8B → 12AB 
B) 2A2 + 4B2 → 4A2B 
C) 2A2 + 4B2 → 4AB2 
D) A2 + B2 → AB2 
E) A2 + 2B2 → 2AB2

Question 14

The specific heat of a substance is the amount of heat energy that is needed to cause the substance to melt.

Accepted Answer

A) True 
 B)False

Question 15

A calorie used by nutritionists, 1 Calorie, is equal to 1000 cal or 1 kcal used by chemists.

Accepted Answer

A) True 
 B)False

Question 16

Consider the reaction between acetylene, C2H2, and oxygen in a welding torch: 2C2H2(g)+ 5O2(g)→ 4CO2(g)+ 2H2O(g)Which of the following is not conserved in this reaction?

Accepted Answer

A) atoms 
B) moles of atoms 
C) moles of molecules 
D) mass 
A) atoms 
B) moles of atoms 
C) moles of molecules 
D) mass

Question 17

What mass (in grams)of SF6 should be produced by the following reaction if 7.00 g of sulfur is mixed with 9.00 g of fluorine? S + 3F2 → SF6

Accepted Answer

A) 24.0 
B) 6.40 
C) 11.1 
D) 32.0 
E) 16.0 
A) 24.0 
B) 6.40 
C) 11.1 
D) 32.0 
E) 16.0

Question 18

Iron metal reacts with hydrochloric acid as follows: 2Fe(s)+ 6HCl(aq)→ 2FeCl3(aq)+ 3H2(g)If 35.6 g of iron react with excess HCl, and 98.6 g of FeCl3 are collected, what is the percent yield of FeCl3?

Accepted Answer

A) 103% 
B) 104% 
C) 95.7% 
D) 63.0% 
E) not enough information given 
A) 103% 
B) 104% 
C) 95.7% 
D) 63.0% 
E) not enough information given

Question 19

When carbon dioxide is formed from its elements, 393.5 kJ of energy is released. Convert this energy to units of calories.

Accepted Answer

A) 9.405 x 104 cal 
B) 94.05 cal 
C) 0.3935 cal 
D) 1.646 x 103 cal 
E) 1.646 x 106 cal 
A) 9.405 x 104 cal 
B) 94.05 cal 
C) 0.3935 cal 
D) 1.646 x 103 cal 
E) 1.646 x 106 cal

Question 20

How much heat energy would be needed to raise the temperature of a 32.0 g sample of gold [C = 0.129 (J/g°C)] from 21.8°C to 75.0°C?

Accepted Answer

A) 3.10 x 102 J 
B) 1.32 x 104 J 
C) 2.20 x 102 J 
D) 90.0 J 
E) not enough information given 
A) 3.10 x 102 J 
B) 1.32 x 104 J 
C) 2.20 x 102 J 
D) 90.0 J 
E) not enough information given

A carton of low-fat yogurt says it has 1.70 x 10² Calories. What is the equivalent amount of energy in units of joules?

In the process of obtaining lead from PbS, or galena, the galena is "roasted" (heated in the presence of oxygen), so that the following reaction occurs: 2PbS(s)+ 3O₂(g)→ 2PbO(s)+ 2SO₂(g)If 35.2 g of PbS is mixed with 15.5 g of oxygen, how many grams of PbO should form?

Consider the reaction between hydrogen and oxygen gases to form water: 2H₂(g)+ O₂(g)→ 2H₂O(l)If 8.5 moles of oxygen react with sufficient hydrogen, how many grams of water should form?

When a substance cools from a high temperature to a low temperature, its heat change value will have a negative sign.

Which of the following is the best (simplest)balanced equation to represent the chemical reaction shown in the figure on any scale?

When acetylene, C₂H₂, a fuel used in welding, is burned in air, two molecules of acetylene combine with five oxygen molecules to form four CO₂ molecules and two H₂O molecules. Select the statement below that is incorrect in regard to this reaction.

A 5.00 g sample of a brownie was burned in a bomb calorimeter containing 2025 g of water. The temperature of the water increased from 23.50°C to 33.47°C. How much heat, in joules, did the brownie release when it burned? [C_water = 4.184 J/(g°C)]

The number of moles of reactant molecules must always equal the number of moles of product molecules in a balanced equation.

When the mixture of molecules shown in the molecular-level image undergoes complete reaction, all of these molecules are converted to products. Which of the following reactions could this represent?

Which of the following is an exothermic process?

Iron metal reacts with hydrochloric acid as follows: 2Fe(s)+ 6HCl(aq)→ 2FeCl₃(aq)+ 3H₂(g)If 22.4 g of iron react with excess HCl, and 59.4 g of FeCl₃ are collected, what is the percent yield of Al₂(SO₄)₃?

Which of the following best describes an exothermic reaction?

Which of the following is the best (simplest)balanced equation to represent the chemical reaction shown in the figure on any scale?

The specific heat of a substance is the amount of heat energy that is needed to cause the substance to melt.

A calorie used by nutritionists, 1 Calorie, is equal to 1000 cal or 1 kcal used by chemists.

Consider the reaction between acetylene, C₂H₂, and oxygen in a welding torch: 2C₂H₂(g)+ 5O₂(g)→ 4CO₂(g)+ 2H₂O(g)Which of the following is not conserved in this reaction?

What mass (in grams)of SF₆ should be produced by the following reaction if 7.00 g of sulfur is mixed with 9.00 g of fluorine? S + 3F₂ → SF₆

Iron metal reacts with hydrochloric acid as follows: 2Fe(s)+ 6HCl(aq)→ 2FeCl₃(aq)+ 3H₂(g)If 35.6 g of iron react with excess HCl, and 98.6 g of FeCl₃ are collected, what is the percent yield of FeCl₃?

When carbon dioxide is formed from its elements, 393.5 kJ of energy is released. Convert this energy to units of calories.

How much heat energy would be needed to raise the temperature of a 32.0 g sample of gold [C = 0.129 (J/g°C)] from 21.8°C to 75.0°C?

Matter and Energy

Atoms, Ions, and the Periodic Table

Chemical Compounds

Chemical Composition

Chemical Reactions and Equations

Electron Structure of the Atom

Chemical Bonding

The Gaseous State

The Liquid and Solid States

Solutions

Reaction Rates and Chemical Equilibrium

Acids and Bases

Oxidation-Reduction Reactions

Nuclear Chemistry

Organic Chemistry

Biochemistry

Filters

Exam 6: Quantities in Chemical Reactions

A carton of low-fat yogurt says it has 1.70 x 102 Calories. What is the equivalent amount of energy in units of joules?

In the process of obtaining lead from PbS, or galena, the galena is "roasted" (heated in the presence of oxygen), so that the following reaction occurs: 2PbS(s)+ 3O2(g)→ 2PbO(s)+ 2SO2(g)If 35.2 g of PbS is mixed with 15.5 g of oxygen, how many grams of PbO should form?

Consider the reaction between hydrogen and oxygen gases to form water: 2H2(g)+ O2(g)→ 2H2O(l)If 8.5 moles of oxygen react with sufficient hydrogen, how many grams of water should form?

When a substance cools from a high temperature to a low temperature, its heat change value will have a negative sign.

Which of the following is the best (simplest)balanced equation to represent the chemical reaction shown in the figure on any scale?

When acetylene, C2H2, a fuel used in welding, is burned in air, two molecules of acetylene combine with five oxygen molecules to form four CO2 molecules and two H2O molecules. Select the statement below that is incorrect in regard to this reaction.

A 5.00 g sample of a brownie was burned in a bomb calorimeter containing 2025 g of water. The temperature of the water increased from 23.50°C to 33.47°C. How much heat, in joules, did the brownie release when it burned? [Cwater = 4.184 J/(g°C)]

The number of moles of reactant molecules must always equal the number of moles of product molecules in a balanced equation.

When the mixture of molecules shown in the molecular-level image undergoes complete reaction, all of these molecules are converted to products. Which of the following reactions could this represent?

Which of the following is an exothermic process?

Iron metal reacts with hydrochloric acid as follows: 2Fe(s)+ 6HCl(aq)→ 2FeCl3(aq)+ 3H2(g)If 22.4 g of iron react with excess HCl, and 59.4 g of FeCl3 are collected, what is the percent yield of Al2(SO4)3?

Which of the following best describes an exothermic reaction?

Which of the following is the best (simplest)balanced equation to represent the chemical reaction shown in the figure on any scale?

The specific heat of a substance is the amount of heat energy that is needed to cause the substance to melt.

A calorie used by nutritionists, 1 Calorie, is equal to 1000 cal or 1 kcal used by chemists.

Consider the reaction between acetylene, C2H2, and oxygen in a welding torch: 2C2H2(g)+ 5O2(g)→ 4CO2(g)+ 2H2O(g)Which of the following is not conserved in this reaction?

What mass (in grams)of SF6 should be produced by the following reaction if 7.00 g of sulfur is mixed with 9.00 g of fluorine? S + 3F2 → SF6

Iron metal reacts with hydrochloric acid as follows: 2Fe(s)+ 6HCl(aq)→ 2FeCl3(aq)+ 3H2(g)If 35.6 g of iron react with excess HCl, and 98.6 g of FeCl3 are collected, what is the percent yield of FeCl3?

When carbon dioxide is formed from its elements, 393.5 kJ of energy is released. Convert this energy to units of calories.

How much heat energy would be needed to raise the temperature of a 32.0 g sample of gold [C = 0.129 (J/g°C)] from 21.8°C to 75.0°C?

Matter and Energy

Atoms, Ions, and the Periodic Table

Chemical Compounds

Chemical Composition

Chemical Reactions and Equations

Electron Structure of the Atom

Chemical Bonding

The Gaseous State

The Liquid and Solid States

Solutions

Reaction Rates and Chemical Equilibrium

Acids and Bases

Oxidation-Reduction Reactions

Nuclear Chemistry

Organic Chemistry

Biochemistry

Filters

A carton of low-fat yogurt says it has 1.70 x 10² Calories. What is the equivalent amount of energy in units of joules?

In the process of obtaining lead from PbS, or galena, the galena is "roasted" (heated in the presence of oxygen), so that the following reaction occurs: 2PbS(s)+ 3O₂(g)→ 2PbO(s)+ 2SO₂(g)If 35.2 g of PbS is mixed with 15.5 g of oxygen, how many grams of PbO should form?

Consider the reaction between hydrogen and oxygen gases to form water: 2H₂(g)+ O₂(g)→ 2H₂O(l)If 8.5 moles of oxygen react with sufficient hydrogen, how many grams of water should form?

When acetylene, C₂H₂, a fuel used in welding, is burned in air, two molecules of acetylene combine with five oxygen molecules to form four CO₂ molecules and two H₂O molecules. Select the statement below that is incorrect in regard to this reaction.

A 5.00 g sample of a brownie was burned in a bomb calorimeter containing 2025 g of water. The temperature of the water increased from 23.50°C to 33.47°C. How much heat, in joules, did the brownie release when it burned? [C_water = 4.184 J/(g°C)]

Iron metal reacts with hydrochloric acid as follows: 2Fe(s)+ 6HCl(aq)→ 2FeCl₃(aq)+ 3H₂(g)If 22.4 g of iron react with excess HCl, and 59.4 g of FeCl₃ are collected, what is the percent yield of Al₂(SO₄)₃?

Consider the reaction between acetylene, C₂H₂, and oxygen in a welding torch: 2C₂H₂(g)+ 5O₂(g)→ 4CO₂(g)+ 2H₂O(g)Which of the following is not conserved in this reaction?

What mass (in grams)of SF₆ should be produced by the following reaction if 7.00 g of sulfur is mixed with 9.00 g of fluorine? S + 3F₂ → SF₆

Iron metal reacts with hydrochloric acid as follows: 2Fe(s)+ 6HCl(aq)→ 2FeCl₃(aq)+ 3H₂(g)If 35.6 g of iron react with excess HCl, and 98.6 g of FeCl₃ are collected, what is the percent yield of FeCl₃?