Deck 8: Chemical Reactivity: Chemicals in Action

Question 1

Which will have the largest molar mass?

A) 1 mol of Ar, argon
B) 1 mol of CO, carbon monoxide
C) 1 mol of N₂, nitrogen
D) 1 mol of Sn, tin

Answer 1

1 mol of Sn, tin

Question 2

Which is not a statement of the First Law of Thermodynamics?

A) Energy can be converted from one form to another.
B) Things are getting more screwed up every day.
C) There's no such thing as a free lunch.
D) You can't get something for nothing.

Answer 2

Things are getting more screwed up every day.

Question 3

What factors determine the rate of a reaction?

A) nature of reactants
B) concentration of reactants
C) activation energy
D) all of these

Answer 3

all of these

Question 4

A catalyst speeds up a reaction rate because it

A) raises the reaction temperature.
B) provides an alternate lower energy pathway.
C) increases the energy of reactants.
D) removes products from the reaction mixture.

Question 5

According to the second law of thermodynamics,

A) The quality of energy is conserved, but he quantity of energy is not conserved.
B) Every naturally occurring process produces some entropy.
C) Perpetual motion is possible.
D) Efficiencies of energy transformations are expected to be 100%.

Question 6

What is the molar mass of H₂SO₄?

A) 50 g
B) 49 g
C) 98 g
D) 7.0 g

Question 7

What numbers are needed to balance the following equation, respectively? ____CO₂ + ____H₂O $\to$ ____C₆H₁₂O₆ + ____O₂

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

Question 8

A chemical reaction that releases heat during the reaction is

A) exothermic.
B) endothermic.
C) a source of quick heat.
D) impossible to reverse.

Question 9

For the equation, H₂(g) + Cl₂(g) $\to$ 2 HCl(g), which statement is false?

A) 1 mol of Cl₂(g) is a reactant.
B) 2 molecules of HCl are formed.
C) 4 g of H₂(g) reacts with 1 mol of Cl₂(g).
D) The sum of the coefficients of the reactants is 2.

Question 10

Which is necessary for a chemical reaction to occur?

A) Reactant molecules must collide.
B) Collisions must be of a certain energy.
C) neither a nor b
D) both a and b

Question 11

Exhibit 8-1
For the following questions, consider the equation below. Zinc will react with a solution of hydrochloric acid to produce hydrogen gas:
Zn(s) + 2 HCl(aq) $\to$ ZnCl₂(s) + H₂(g)

-Refer to Exhibit 8-1. The atomic weights for Zn, H and Cl are 65.4 g, 1.0 g and 35.5 g, respectively. What is the mass for two moles of hydrochloric acid?

A) 36.5 g
B) 71.0 g
C) 35.5 g
D) 73.0 g

Question 12

In all chemical changes,

A) reactants disappear completely.
B) all of the reactants must cease to exist.
C) the weight of products and reactants must balance.
D) products must be in the same physical state as the reactants.

Question 13

According to the first law of thermodynamics,

A) Energy is neither lost nor gained in an energy transformation.
B) Perpetual motion is possible.
C) Energy is not conserved.
D) Energy is being created as time passes.

Question 14

For the equation, 2 NaN₃(s) $\to$ 2 Na(s) + 3 N₂(g), which statement is false?

A) The equation is balanced.
B) The products are sodium and nitrogen.
C) The sum of all coefficients is 7.
D) The products are all in the same state of matter.

Question 15

Preserving food by freezing controls reaction rates by

A) decreasing the number of collisions.
B) increasing concentration.
C) changing the number of effective reactant collisions.
D) Both a and c are correct.

Question 16

Exhibit 8-1
For the following questions, consider the equation below. Zinc will react with a solution of hydrochloric acid to produce hydrogen gas:
Zn(s) + 2 HCl(aq) $\to$ ZnCl₂(s) + H₂(g)

-Refer to Exhibit 8-1. What weight of ZnCl₂ will be produced from 1.00 mol of Zn?

A) 65.4 g
B) 98.9 g
C) 136 g
D) 71.0 g

Question 17

If 2 pounds of hydrogen react with chlorine to form 73 pounds of hydrogen chloride, what weight of chlorine must react with the 2 lb of hydrogen?
H₂(g) + Cl₂(g) $\to$ 2 HCl(g)

A) 71 lb Cl₂(g)
B) 35.5 lb Cl₂(g)
C) 2 lb Cl₂(g)
D) The weight of chlorine used depends on the reaction conditions.

Question 18

If you add more CO₂(g) to an equilibrium mixture of CaCO₃(s), CaO(s) and CO₂(g) in a hot closed vessel, which way would you expect the equilibrium to shift ? CaCO₃(s)
CaO(s) + CO₂(g)

A) to form more reactant
B) to form more product
C) no change
D) indeterminable based in information given

Question 19

Exhibit 8-1
For the following questions, consider the equation below. Zinc will react with a solution of hydrochloric acid to produce hydrogen gas:
Zn(s) + 2 HCl(aq) $\to$ ZnCl₂(s) + H₂(g)

-Refer to Exhibit 8-1. How many moles of hydrochloric acid react with one mole of zinc?

A) 1 mol
B) 2 mol
C) between 1 and 2 mol depending on how much hydrogen gas is formed
D) the same number as the number of moles of hydrogen produced

Question 20

Which will increase the rate of a reaction?

A) increasing temperature
B) increasing temperature and concentration
C) increasing temperature and surface area
D) all of these

Question 21

What is conserved when one balances a chemical equation?

A) molecules
B) atoms
C) products
D) reactants

Question 22

How does changing concentration effect the rate of a chemical reaction?

A) Increasing the concentration of a reactant will increase the reaction rate.
B) The concentration has very little effect on reaction rates.
C) The reaction rate increases only when all reactant concentrations are increased.
D) Increasing the concentration of products increases reaction rates.

Question 23

Which is a statement of the Second Law of Thermodynamics?

A) Energy can be converted from one form to another.
B) Things are getting more screwed up every day.
C) There's no such thing as a free lunch.
D) You can't get something for nothing.

Question 24

The use of a fire blanket in extinguishing a clothing fire is most closely related to what factor relative to chemical reaction rates?

A) temperature of reaction medium
B) catalysis
C) equilibrium ratio of reactants and products
D) concentration of reactants

Question 25

Chemical equilibrium exists for a chemical reaction when

A) equal amounts of chemicals exist on reactant and product sides.
B) one or more of the reactants are used completely.
C) all molecular activity stops.
D) a state of balance exists between two opposite changes occurring at the same rate.

Question 26

How many atoms are represented in the formula Ca₃(PO₄)₂?

A) 9
B) 11
C) 13
D) 1

Question 27

Crumpling the pages of a newspaper to start a fire increases

A) surface contact.
B) reactant available.
C) equilibrium constant.
D) temperature effect on reaction rate.

Question 28

What is the mass of one mole of water molecules, H₂O? The atomic weight of hydrogen is 1 and the atomic weight of oxygen is 16.

A) 18 g H₂O
B) 18 H₂O
C) 6.02 $\times$ 10²³ g H₂O
D) 6.02 $\times$ 10²³ H₂O

Question 29

The three R's of waste prevention include

A) reuse products as much as possible.
B) recycle materials as much as possible.
C) reduce the amount of waste as much as possible.
D) all of the above

Question 30

If you remove some CO₂(g) from an equilibrium mixture of CaCO₃(s), CaO(s) and CO₂(g) in a hot closed vessel, which way would you expect the equilibrium to shift ? CaCO₃(s)
CaO(s) + CO₂(g)

A) to form more reactant
B) to form more product
C) no change
D) indeterminable based in information given

Question 31

If you add more CaCO₃(s) to an equilibrium mixture of CaCO₃(s), CaO(s) and CO₂(g) in a hot closed vessel, which way would you expect the equilibrium to shift ? CaCO₃(s)
CaO(s) + CO₂(g)

A) to form more reactant
B) to form more product
C) no change
D) indeterminable based in information given

Question 32

What is the sum of the coefficients when the following equation is balanced? Fe(s) + O₂(g) $\to$ Fe₂O₃(s)

A) 3
B) 6
C) 9
D) 10

Question 33

How many grams are in 2.40 mol of carbon tetrachloride?

A) 0.0156 g
B) 370 g
C) 114 g
D) 0.0506 g

Question 34

What reaction rate factor is responsible for a dust explosion in a flour mill?

A) increased temperature
B) increased surface area
C) presence of catalysis
D) foreign chemicals

Question 35

Favorable chemical reactions

A) are generally explosive.
B) absorb energy from the surroundings.
C) occur only in the gaseous phase.
D) usually give off heat energy.

Question 36

How many moles are in 15.5 g of diphosphorous pentoxide?

A) 0.109 mol
B) 0.330 mol
C) 6.56 $\times$ 10²³ mol
D) 2.20 $\times$ 10³ mol

Question 37

What is the number of atoms in 1.0 mol of nitrogen dioxide, NO₂?

A) 1.8 $\times$ 10²⁴ atoms
B) 1.8 $\times$ 10²³ atoms
C) 2.0 $\times$ 10²³ atoms
D) 3 atoms

Question 38

What is the coefficient of oxygen when the following molecular equation is correctly balanced? _____NH₃(g) + _____O₂(g) $\to$ _____NO(g) + _____H₂O(g)

A) 1
B) 2
C) 3
D) 4
E) 5

Question 39

Le Châtelier's principle says

A) equilibrium mixtures are changed only when reactants are added.
B) equilibrium mixtures will change to form more products when a reactant is added.
C) the balance between reactants and products is not altered by changing the product concentration.
D) equilibrium mixtures will not change when a stress is placed on the system.

Question 40

Which of the following samples has the most entropy?

A) 1 mol solid hydrogen
B) 1 mol liquid hydrogen
C) 1 mol hydrogen gas
D) All are the same because they are all hydrogen.

Question 41

Consider the following two statements.
"Energy can be converted from one form to
another but cannot be destroyed nor created."
"The total amount of matter and
energy in the universe is constant."
Both of these are included in the first law of thermodynamics.

Question 42

Consider the following reaction.
PCl₅(g) PCl₃(g) + Cl₂(g)
If the pressure is increased the forward reaction will be favored.

Question 43

Consider the following energy profile for a reaction. Answer with the following questions with the letters shown in the profile.
E_reaction is represented by the letter ________.

Question 44

An indicator, HIn, shows a color change from blue to yellow, depending on the acidity of the solution: HIn (aq) + H₂O(l) H₃O⁺ (aq) + In^- (aq)
(blue) (yellow)
What color will the indicator be if vinegar is added to this solution?

A) blue
B) yellow
C) Addition of vinegar will have not effect on the indicator color.

Question 45

Consider the following energy profile for a reaction. Answer with the following questions with the letters shown in the profile.
The reactants are represented by the letter _______.

Question 46

Addition of a catalyst to a reaction and increasing the temperature of a reaction generally have the same effect on the reaction rate.

Question 47

In the following reaction, the products have lower entropy than the reactants.
CaCO₃(s)
CaO(s) + CO₂(g)

Question 48

The molar mass of sulfur trioxide is ________g.

Question 49

The following energy profile represents an
exergonic reaction.

Question 50

Consider the following energy profile for a reaction. Answer with the following questions with the letters shown in the profile.
If a catalyst were added to this reaction, the position of letter ______ would appear lower on the energy scale.

Question 51

The mass of 1 mol of Ar is smaller than the mass of 1 mol of CO₂.

Question 52

Consider the following energy profile for a reaction. Answer with the following questions with the letters shown in the profile.
E_act is represented by the letter_______.

Question 53

For a reaction to take place, the molecules that are reacting

A) must have more energy than the products.
B) must have less energy than the products.
C) must be able to reach to activation energy.
D) must be present in large numbers.

Question 54

Consider the following energy profile for a reaction. Answer with the following questions with the letters shown in the profile.
The products of the reaction are presented by the letter________.