Question

1.

Which of the following is not a definition of an acid?

A substance that increases the hydroxide ion concentration of a solution

A hydrogen ion donor in a reaction

A substance that increases the hydronium ion concentration of a solution

An electron-pair acceptor in a reaction
2.
What is true of an acidic solution at room temperature?

It is slippery to the touch.

It has a bitter taste.

It has a pH value below 7.

It can neutralize HCl.
3.
Which of the following solutions will not neutralize a base solution?

Vinegar

Ammonia

HCl

HNO3
4.
What is true of a basic solution at room temperature?

It has a pH value below 7.

It has a higher concentration of hydroxide ions than hydronium ions.

It has a distinct sour taste but no odor.

It releases hydrogen ions in a reaction.
5.
Which of the following is the best explanation why a reaction in a closed container can appear to stop before all the reactants are converted to products?

The forward reaction has run to completion, and the reverse reaction has started.

The reaction reaches equilibrium, and the forward and reverse reactions stop.

The forward and reverse reactions eventually reach the same rate.

The limiting reactant prevents the forward reaction from continuing to completion.
6.
Which of the following would shift the equilibrium to the right in the following reaction?
C2H2 + H2O Two arrows stacked on top of each other. The top arrow points to the right. The bottom arrow points to the left. CH3CHO


Removing H2O (g) from the system

Adding CH3CHO (g) to the system

Removing C2H2 (g) from the system

Adding H2O (g) to the system
7.
In the equilibrium system below, which of the following changes would cause the equilibrium position to shift to the right?
CO(g) + 3H2 (g) Two arrows stacked on top of each other. The top arrow points to the right. The bottom arrow points to the left. CH4 (g) + H2O (g) + Energy


Decreasing the concentration of carbon monoxide (CO)

Increasing the volume of the reaction system

Decreasing the concentration of hydrogen gas (H2)

Lowering the temperature of the reaction
8.
Which of the following correctly describes an oxidation-reduction reaction?

The element that is oxidized increases in electronegativity, and the element that is reduced decreases in electronegativity.

The element that is oxidized decreases in electronegativity, and the element that is reduced increases in electronegativity.

The element that is oxidized loses electrons, and the element that is reduced gains electrons.

The element that is oxidized gains electrons, and the element that is reduced loses electrons.
9.
Rusting is a chemical process that changes the strength and integrity of objects made of iron or iron alloys. Which of the following statements correctly describes the rusting process below?
4 Fe(s) + 3O2 (g) yields 2 Fe2O3 (s)


Iron is oxidized because it gained electrons.

Iron is oxidized because it lost electrons.

Oxygen is oxidized because it gains electrons.

Oxygen is oxidized because it lost electrons.
10.
What is a major difference between a chemical reaction and a nuclear reaction?

Only nuclear reactions release energy.

Only chemical reactions release light.

Only chemical reactions can release gamma rays.

Only nuclear reactions can change the identity of the atom.
11.
Which of the following best compares a fission reaction and a fusion reaction?

Both reactions absorb energy; in a fission reaction, two smaller atoms combine to form one larger atom, while in a fusion reaction, one large atom splits into smaller atoms.

Both reactions absorb energy; in a fission reaction, one atom splits into two smaller atoms, while in a fusion reaction, two smaller atoms combine to form one larger atom.

Both reactions release energy; in a fission reaction, two smaller atoms combine to form one larger atom, while in a fusion reaction, one large atom splits into smaller atoms.

Both reactions release energy; in a fission reaction, one atom splits into two smaller atoms, while in a fusion reaction, two smaller atoms combine to form one larger atom.

Answer 1

1. The answer is A hydrogen ion donor in a reaction. On the other hand a base is a substance that increases the hydroxide ion concentration of a solution. How strong an acid depends on the degree of dissociation to release H+ ions in water

2. The answer is It has a pH value below 7. pH is logarithm base 10 of the reciprocal of the amount of H+ions in a solution. Acids have a sour taste while bases have bitter tastes. Acids also turn litmus paper red.

3. The answer is ammonia. Aqueous ammonia is basic in pH (pH above 7). The other given choices are acids or dissociates into acids in aqueous form. When a base and acid are mixed, the products are water and salts in a process called neutralization.

4. The answer is It has a higher concentration of hydroxide ions than hydronium ions. As indicated in question 1, while acids dissociate to release more of H+ ions, bases dissociate to release more of –OH ions. The stronger the base the more it dissociates –OH ions in water.

5. The answer is The forward and reverse reactions eventually reach the same rate. This occurs when in the forwards reaction the reactants form products, and subsequently, the products also reverse back to the former reactants. The forward process begins and continues until there are enough products and the reversing back of products to reactants is in equilibrium with the forward reaction.

6. The answer is Adding H2O (g) to the system. Increasing reactants in a chemical reaction pushes the reaction forwards. Also reducing the products also pushes the reaction forwards. The reverse also applies where increasing the products pushes the reaction in the reverse.

7. The answer is Lowering the temperature of the reaction. According to the reaction, it release heat as a product hence it is exothermic. Removing this heat energy by keeping the reaction cool pushes the reaction forward. This is tantamount to reducing products in the reaction.

8. The answer is The element that is oxidized loses electrons, and the element that is reduced gains electrons. An example of redox reaction is rusting process and combustion.

9. The answer is Iron is oxidized because it lost electrons. Oxygen is reduced, on the other hand, by accepting an electron from iron. This is why Iron turns from iron II to iron III in rusting process.

10. The answer is Only nuclear reactions can change the identity of the atom. In nuclear reaction, a heavy element atom decays into another element atom and releases a neutron and energy. In chemical reactions, atoms remain the same, they only make new bonds with one another.

11. The answer is Both reactions release energy; in a fission reaction, one atom splits into two smaller atoms, while in a fusion reaction, two smaller atoms combine to form one larger atom. An example of Fusion reaction is that which occurs in the center of the stars while a fission reaction is that which occurs in nuclear fission bombs.