Question 1

What is the oxidation number of Br in   ?

Accepted Answer

A) − 1 
B) +1 
C) +2 
D) +3 
A) − 1 
B) +1 
C) +2 
D) +3

Question 2

Lycopene, a phytonutrient, has several potential health benefits, including protection against prostate, cervical and pancreatic cancer.  Which of the following is a good source of this substance?

Accepted Answer

A) spinach 
B) broccoli 
C) strawberries 
D) tomatoes 
A) spinach 
B) broccoli 
C) strawberries 
D) tomatoes

Question 3

Suppose 2.43 g of magnesium is reacted with 3.20 g of oxygen: 2Mg + O2 → 2MgO. How many grams of MgO will be produced?

Accepted Answer

A) 5.63 
B) 1.27 
C) 8.06 
D) 4.03 
A) 5.63 
B) 1.27 
C) 8.06 
D) 4.03

Question 4

Which of the following conversion factors would allow one to calculate the amount of PbI2 produced from a given amount of NaI in the following unbalanced reaction? Pb(NO3)2 + Nal   →   Pbl2 + NaNO3

Accepted Answer

A)    
B)    
C)    
D)    
A)    
B)    
C)    
D)

Question 5

What substance is reduced in the following reaction? 4HCl + MnO2 → Cl2 + 2H2O + MnCl2

Accepted Answer

A) Cl in HCl 
B) Mn in MnO2 
C) H in HCl 
D) O in MnO2 
A) Cl in HCl 
B) Mn in MnO2 
C) H in HCl 
D) O in MnO2

Question 6

Which set of coefficients balances the equation? ____ CH4 → ____ C3H8 + ____ H2

Accepted Answer

A) 3,1,1 
B) 3,2,1 
C) 3,1,2 
D) 6,2,2 
A) 3,1,1 
B) 3,2,1 
C) 3,1,2 
D) 6,2,2

Question 7

Redox reactions may also be a decomposition reaction.

Accepted Answer

A) True 
 B)False

Question 8

Which of the following is a double replacement reaction?

Accepted Answer

A) CuO + H2 → Cu + H2O 
B) HBr + KOH → H2O + KBr 
C) SO2 + H2O → H2SO3 
D) 2HI → I2 + H2 
A) CuO + H2 → Cu + H2O 
B) HBr + KOH → H2O + KBr 
C) SO2 + H2O → H2SO3 
D) 2HI → I2 + H2

Question 9

The reaction below would be considered  _____ . CaCO3 + heat   →   CaO + CO2

Accepted Answer

A) an endothermic combination. 
B) an exothermic combination. 
C) an endothermic decomposition. 
D) an exothermic decomposition. 
A) an endothermic combination. 
B) an exothermic combination. 
C) an endothermic decomposition. 
D) an exothermic decomposition.

Question 10

A percentage yield greater than 100% has been reported in a scientific paper you are assigned to read. What would be a reasonable explanation for this?

Accepted Answer

A) A lack of training of the professor who published the study. 
B) The product was measured more than once. 
C) Small measurement errors could have caused this to occur. 
D) It must be a typographical error since yields can't exceed 100%. 
A) A lack of training of the professor who published the study. 
B) The product was measured more than once. 
C) Small measurement errors could have caused this to occur. 
D) It must be a typographical error since yields can't exceed 100%.

Question 11

The energy involved in chemical reactions

Accepted Answer

A) always appears as heat. 
B) always appears as light. 
C) always appears as electricity. 
D) can take many forms. 
A) always appears as heat. 
B) always appears as light. 
C) always appears as electricity. 
D) can take many forms.

Question 12

All redox reactions involve oxygen.

Accepted Answer

A) True 
 B)False

Question 13

​ What is the oxidation number of an uncombined element?

Accepted Answer

A) +1 
B) −1 
C) 0 
D) −2 
A) +1 
B) −1 
C) 0 
D) −2

Question 14

If 5 grams of CO and 5 grams of O2 are combined according to the reaction, which is the limiting reagent?  2CO + O2 → 2CO2

Accepted Answer

A) CO2 
B) O2 
C) CO 
D) CO and O2 
A) CO2 
B) O2 
C) CO 
D) CO and O2

Question 15

Which of the following is a combination reaction?

Accepted Answer

A) SO2 + O2 → 2SO3 
B) 2C2H2 + 5O2 → 4CO2 + 2H2O 
C) 2H2O2 → 2H2O + O2 
D) AgNO3 + NaCl → AgCl + NaNO3 
A) SO2 + O2 → 2SO3 
B) 2C2H2 + 5O2 → 4CO2 + 2H2O 
C) 2H2O2 → 2H2O + O2 
D) AgNO3 + NaCl → AgCl + NaNO3

Question 16

Which of the following types of chemical reaction classes always involve oxidation?

Accepted Answer

A) single replacement 
B) double replacement 
C) combination 
D) decomposition 
A) single replacement 
B) double replacement 
C) combination 
D) decomposition

Question 17

According to the law of conservation of matter, which of the following may NEVER occur as a result of a chemical reaction?

Accepted Answer

A) creation of new chemical species. 
B) reaction of starting materials. 
C) rearranged to form new substances. 
D) reduction in total mass. 
A) creation of new chemical species. 
B) reaction of starting materials. 
C) rearranged to form new substances. 
D) reduction in total mass.

Question 18

What is the oxidation number of Cl in HClO3?

Accepted Answer

A) +2 
B) +3 
C) +4 
D) +5 
A) +2 
B) +3 
C) +4 
D) +5

Question 19

Which of the following reactions is correctly balanced?

Accepted Answer

A) N2 + H → 2NH3 
B) 2H2O + C → CO + 2H2 
C) Zn + 2HCl → H2 + ZnCl2 
D) CO + O2 → CO2 
A) N2 + H → 2NH3 
B) 2H2O + C → CO + 2H2 
C) Zn + 2HCl → H2 + ZnCl2 
D) CO + O2 → CO2

Question 20

In ionic compounds, metals have a positive oxidation number.

Accepted Answer

A) True 
 B)False

Exam 5: Chemical Reactions

What is the oxidation number of Br in ?

Lycopene, a phytonutrient, has several potential health benefits, including protection against prostate, cervical and pancreatic cancer. Which of the following is a good source of this substance?

Suppose 2.43 g of magnesium is reacted with 3.20 g of oxygen: 2Mg + O2 → 2MgO. How many grams of MgO will be produced?

Which of the following conversion factors would allow one to calculate the amount of PbI2 produced from a given amount of NaI in the following unbalanced reaction? Pb(NO3)2 + Nal → Pbl2 + NaNO3

What substance is reduced in the following reaction? 4HCl + MnO2 → Cl2 + 2H2O + MnCl2

Which set of coefficients balances the equation? ____ CH4 → ____ C3H8 + ____ H2

Redox reactions may also be a decomposition reaction.

Which of the following is a double replacement reaction?

The reaction below would be considered _____ . CaCO3 + heat → CaO + CO2

A percentage yield greater than 100% has been reported in a scientific paper you are assigned to read. What would be a reasonable explanation for this?

The energy involved in chemical reactions

All redox reactions involve oxygen.

​ What is the oxidation number of an uncombined element?

If 5 grams of CO and 5 grams of O2 are combined according to the reaction, which is the limiting reagent? 2CO + O2 → 2CO2

Which of the following is a combination reaction?

Which of the following types of chemical reaction classes always involve oxidation?

According to the law of conservation of matter, which of the following may NEVER occur as a result of a chemical reaction?

What is the oxidation number of Cl in HClO3?

Which of the following reactions is correctly balanced?

In ionic compounds, metals have a positive oxidation number.

Matter, Measurements, and Calculations

Atoms and Molecules

Electronic Structure and the Periodic Law

Forces Between Particles

The States of Matter

Solutions and Colloids

Reaction Rates and Equilibrium

Acids, Bases, and Salts

Radioactivity and Nuclear Processes

Organic Compounds: Alkanes

Unsaturated Hydrocarbons

Alcohols, Phenols, and Ethers

Aldehydes and Ketones

Carboxylic Acids and Esters

Amines and Amides

Carbohydrates

Lipids

Proteins

Enzymes

Nucleic Acids and Protein Synthesis

Nutrition and Energy for Life

Carbohydrate Metabolism

Lipid and Amino Acid Metabolism

Body Fluids

Filters

Suppose 2.43 g of magnesium is reacted with 3.20 g of oxygen: 2Mg + O₂ → 2MgO. How many grams of MgO will be produced?

Which of the following conversion factors would allow one to calculate the amount of PbI₂ produced from a given amount of NaI in the following unbalanced reaction? Pb(NO₃)₂ + Nal → Pbl₂ + NaNO₃

What substance is reduced in the following reaction? 4HCl + MnO₂ → Cl₂ + 2H₂O + MnCl₂

Which set of coefficients balances the equation? CH₄ → C₃H₈ + H₂

The reaction below would be considered _____ . CaCO₃ + heat → CaO + CO₂

What is the oxidation number of an uncombined element?

If 5 grams of CO and 5 grams of O₂ are combined according to the reaction, which is the limiting reagent? 2CO + O₂ → 2CO₂

What is the oxidation number of Cl in HClO₃?