Question 1

What is a chemical reaction?

Accepted Answer

A)  when one or more new compounds are formed by rearranging atoms
B)  when a new element is formed by rearranging nucleons
C)  when two solids mix together to form a heterogeneous mixture
D)  when two liquids mix to form a homogeneous mixture
E)  when a liquid undergoes a phase change and produces a solidF) B) and E)
G) D) and E) A

Question 2

How many grams of water can be formed from the reaction between 10 grams of oxygen and 1 gram of hydrogen?

Accepted Answer

A)  11 grams of water are formed since mass must be conserved.
B)  10 grams of water are formed since you can't get a greater mass of water produced than oxygen reacting.
C)  9 grams of water are formed because oxygen and hydrogen react in an 8:1 ratio.
D)  No water is formed because there is insufficient hydrogen to react with the oxygen.E) A) and C)
F) B) and C)

Question 3

Balance these equations. ____ H2 (g) + ____ N2 (g) → ____ NH3 (g)

Accepted Answer

A)  2, 2, 3
B)  2, 2, 5
C)  3, 3, 2
D)  3, 1, 2E) All of the above
F) A) and B)

Question 4

Given that the above energy profiles have the same scale, which of the reactions would require the most energy?

Accepted Answer

A)  a
B)  b
C)  c
D)  d
E)  none of the aboveF) D) and E)
G) A) and E)

Question 5

Which equations are balanced? 
A.Mg (s) + 2HCl (aq) → MgCl2 (aq) + H2 (g) 
B.3Al (s) + 3 Br2 (l) → Al2Br3 (s) 
C.2HgO (s) → 2 Hg (l) + O2 (g)

Accepted Answer

A)  Only equation "c" is balanced.
B)  Equations "a" and "c" are balanced.
C)  Equations "b" and "c" are balanced.
D)  All of them are balanced.E) A) and C)
F) A) and D)

Question 6

According to the following balanced chemical equation, if you want to generate two moles of H2O how many grams of O2 do you need? 2 H2 + O2 → 2 H2O

Accepted Answer

A)  32
B)  16
C)  8
D)  4
E)  6.022 × 1023F) None of the above
G) B) and C)

Question 7

If the relative mass of a pingpong ball is 1/20 that of a golf ball, how many pingpong balls would you need to equal the mass of two golf balls?

Accepted Answer

A)  40
B)  20
C)  24
D)  100
E)  6.022 × 1023F) A) and E)
G) B) and C)

Question 8

If it takes energy to break bonds and you gain energy in the formation of bonds, how can some reactions be exothermic while others are endothermic?

Accepted Answer

A)  It is the total amount of energy that matters. Sometimes some bonds are stronger than others and so you gain or lose energy when you form them.
B)  It is the total number of bonds that matters. Sometimes you create more bonds than you break and since all bonds have same amount of energy you gain or lose energy depending on the number of bonds.
C)  Some reactants have more energetic bonds than others and they will always release energy.
D)  Some products have more energy than others and they always require energy to be formed.
E)  none of the aboveF) A) and D)
G) B) and D)

Question 9

How is ozone produced in the upper atmosphere?

Accepted Answer

A)  It forms by reaction of oxygen molecules with UV light.
B)  It forms by nuclear decomposition of oxygen.
C)  It diffuses from the lower atmosphere.
D)  It forms by the reaction of nitric dioxide and oxygen.
E)  all of the aboveF) A) and C)
G) None of the above

Question 10

What is the formula mass of a molecule of C6H12O6?

Accepted Answer

A)  180 amu
B)  24 amu
C)  29 amu
D)  168 amu
E)  none of the aboveF) C) and D)
G) B) and E) A

Question 11

What is an endothermic reaction?

Accepted Answer

A)  It is a reaction that requires heat as a reactant.
B)  It is a reaction where the products have more energy than the reactants.
C)  It is a reaction where there is a net adsorption of energy from a reaction.
D)  all of the above
E)  none of the aboveF) D) and E)
G) A) and E)

Question 12

Wild plants readily grow "all by themselves" yet the molecules of the growing plant have less entropy than the materials used to make the plant. How is it possible for a there to be this decrease in entropy for a process that occurs all by itself?

Accepted Answer

A)  A decrease in entropy does not necessarily mean that a reaction if favored to proceed on its own. It happens in this instance but not in others.
B)  There is no decrease in entropy when wild plants grow. All growing plants tend to display an increase in entropy.
C)  Wild plants don't grow "all by themselves." When we consider the entire system, including the sun, we find an overall increase in entropy.
D)  Life on Earth "arises on its own." It does not depend on entropy processes.E) B) and D)
F) All of the above

Question 13

For the following balanced equation, which has the highest coefficient? 4 H2 + 2 C → 2 CH4

Accepted Answer

A)  H2
B)  C
C)  CH4
D)  H4
E)  none of the aboveF) B) and C)
G) B) and E)

Question 14

How many moles of water, H2O, are produced from the reaction of 16 grams methane, CH4, with an unlimited supply of oxygen, O2. How many grams of H2O is this? CH4 + 2 O2 → CO2 + 2 H2O

Accepted Answer

A)  0.889 mole, which is 16 grams
B)  2.0 moles of water, which is 32 grams
C)  2.0 moles of water, which is 36 grams
D)  1.0 mole of water, which is 18 gramsE) A) and D)
F) B) and D)

Question 15

How many grams of water, H2O, and propene, C3H6, can be formed from the reaction of 6.0 g of 2-propanol, C3H8O? C3H8O → C3H6 + H2O
2-Propanol Propene Water

Accepted Answer

A)  6.0 grams of propene, 0.0 grams of water
B)  1.8 grams of propene, 4.2 grams of water
C)  0.0 grams of propene, 6.0 grams of water
D)  4.2 grams of propene, 1.8 grams of waterE) A) and C)
F) None of the above

Question 16

Carefully examine the following reaction sequence for the catalytic formation of ozone, O3, from molecular oxygen, O2. Which chemical compound is behaving as the catalyst? O2 + 2 NO → 2 N O2
2 N O2 → 2 NO + 2 O
2 O + 2 O2 → 2 O3

Accepted Answer

A)  Nitrogen monoxide, NO
B)  Nitrogen dioxide, N O2
C)  Oxygen, O2
D)  Atomic oxygen, OE) B) and C)
F) A) and D)

Question 17

Which of the following is a correctly balanced equation?

Accepted Answer

A)  P4 + 6 H2 → 4 PH3
B)  1 P4 + 6 H2 → 4 PH3
C)  0 P4 + 6 H2 → 4 PH3
D)  2 P4 + 12 H2 → 8 PH3
E)  P4 + 3 H2 → PH3F) C) and D)
G) B) and E) A

Question 18

What is a chemical equation?

Accepted Answer

A)  It is a shorthand notation for illustrating a chemical reaction.
B)  It is the sum of the masses of the products and reactants.
C)  It is the chemical combination of equal numbers of reactants and products.
D)  It is a picture of the atoms undergoing a chemical equalization.
E)  It is any type of reaction that takes place at the equator.F) A) and D)
G) A) and C)

Question 19

If the relative mass of a hydrogen atom is 1/4 that of a helium atom, how many helium atoms would you need to equal the mass of 200 hydrogen atoms?

Accepted Answer

A)  50
B)  200
C)  800
D)  4
E)  100F) A) and E)
G) A) and D)

Question 20

Why do the natural reactions involving ozone not lead to depletion of the ozone layer?

Accepted Answer

A)  Ozone continually rises from the troposphere.
B)  Ozone is too diffuse.
C)  Ozone breaks into fragments that can reassemble into more ozone.
D)  UV radiation generates more ozone.
E)  c and dF) A) and B)
G) A) and C)

Exam 17: How Chemicals React

What is a chemical reaction?

Correct AnswerverifiedA

How many grams of water can be formed from the reaction between 10 grams of oxygen and 1 gram of hydrogen?

Correct AnswerverifiedShow Answer

Balance these equations. ____ H2 (g) + ____ N2 (g) → ____ NH3 (g)

Correct AnswerverifiedShow Answer

Given that the above energy profiles have the same scale, which of the reactions would require the most energy?

Correct AnswerverifiedShow Answer

Which equations are balanced? A.Mg (s) + 2HCl (aq) → MgCl2 (aq) + H2 (g) B.3Al (s) + 3 Br2 (l) → Al2Br3 (s) C.2HgO (s) → 2 Hg (l) + O2 (g)

Correct AnswerverifiedShow Answer

According to the following balanced chemical equation, if you want to generate two moles of H2O how many grams of O2 do you need? 2 H2 + O2 → 2 H2O

Correct AnswerverifiedShow Answer

If the relative mass of a pingpong ball is 1/20 that of a golf ball, how many pingpong balls would you need to equal the mass of two golf balls?

Correct AnswerverifiedShow Answer

If it takes energy to break bonds and you gain energy in the formation of bonds, how can some reactions be exothermic while others are endothermic?

Correct AnswerverifiedShow Answer

How is ozone produced in the upper atmosphere?

Correct AnswerverifiedShow Answer

What is the formula mass of a molecule of C6H12O6?

Correct AnswerverifiedA

What is an endothermic reaction?

Correct AnswerverifiedShow Answer

Wild plants readily grow "all by themselves" yet the molecules of the growing plant have less entropy than the materials used to make the plant. How is it possible for a there to be this decrease in entropy for a process that occurs all by itself?

Correct AnswerverifiedShow Answer

For the following balanced equation, which has the highest coefficient? 4 H2 + 2 C → 2 CH4

Correct AnswerverifiedShow Answer

How many moles of water, H2O, are produced from the reaction of 16 grams methane, CH4, with an unlimited supply of oxygen, O2. How many grams of H2O is this? CH4 + 2 O2 → CO2 + 2 H2O

Correct AnswerverifiedShow Answer

How many grams of water, H2O, and propene, C3H6, can be formed from the reaction of 6.0 g of 2-propanol, C3H8O? C3H8O → C3H6 + H2O 2-Propanol Propene Water

Correct AnswerverifiedShow Answer

Carefully examine the following reaction sequence for the catalytic formation of ozone, O3, from molecular oxygen, O2. Which chemical compound is behaving as the catalyst? O2 + 2 NO → 2 N O2 2 N O2 → 2 NO + 2 O 2 O + 2 O2 → 2 O3

Correct AnswerverifiedShow Answer

Which of the following is a correctly balanced equation?

Correct AnswerverifiedA

What is a chemical equation?

Correct AnswerverifiedShow Answer

If the relative mass of a hydrogen atom is 1/4 that of a helium atom, how many helium atoms would you need to equal the mass of 200 hydrogen atoms?

Correct AnswerverifiedShow Answer

Why do the natural reactions involving ozone not lead to depletion of the ozone layer?

Correct AnswerverifiedShow Answer

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Balance these equations. H₂ (g) + N₂ (g) → NH₃ (g)

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Which equations are balanced? A.Mg (s) + 2HCl (aq) → MgCl₂ (aq) + H₂(g) B.3Al (s) + 3 Br₂ (l) → Al₂Br₃ (s) C.2HgO (s) → 2 Hg (l) + O₂ (g)

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According to the following balanced chemical equation, if you want to generate two moles of H₂O how many grams of O₂ do you need? 2 H₂ + O₂ → 2 H₂O

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What is the formula mass of a molecule of C₆H₁₂O₆?

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For the following balanced equation, which has the highest coefficient? 4 H₂ + 2 C → 2 CH₄

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How many moles of water, H₂O, are produced from the reaction of 16 grams methane, CH₄, with an unlimited supply of oxygen, O₂. How many grams of H₂O is this? CH₄ + 2 O₂ → CO₂ + 2 H₂O

Correct Answer
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How many grams of water, H₂O, and propene, C₃H₆, can be formed from the reaction of 6.0 g of 2-propanol, C₃H₈O? C₃H₈O → C₃H₆ + H₂O 2-Propanol Propene Water

Correct Answer
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Carefully examine the following reaction sequence for the catalytic formation of ozone, O₃, from molecular oxygen, O₂. Which chemical compound is behaving as the catalyst? O₂ + 2 NO → 2 N O₂ 2 N O₂ → 2 NO + 2 O 2 O + 2 O₂ → 2 O₃

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