Rate Of Reaction Quiz Questions

1. The rate of reaction increases as the temperature increases. Which of the following statements provides the best explanation for this?

At lower temperatures the particles do not collide with each other

At higher temperatures the particles have more energy, move faster and collide more often

Increasing the temperature increases the number of particles, so they collide more often

At higher temperatures, the particles in a reaction have more energy and move faster. This increased energy and movement result in more frequent collisions between particles. According to the collision theory, a reaction can only occur when particles collide with enough energy and in the correct orientation. Therefore, when the temperature is increased, the rate of reaction increases because there are more collisions happening with sufficient energy and correct orientation, leading to a higher likelihood of successful reactions.

Explanation

At higher temperatures, the particles in a reaction have more energy and move faster. This increased energy and movement result in more frequent collisions between particles. According to the collision theory, a reaction can only occur when particles collide with enough energy and in the correct orientation. Therefore, when the temperature is increased, the rate of reaction increases because there are more collisions happening with sufficient energy and correct orientation, leading to a higher likelihood of successful reactions.

2. Marble reacts with hydrochloric acid to produce calcium chloride, water and carbon dioxide. In which of these mixtures is the rate of reaction likely to be the greatest?

1g of marble chips in 100cm3 of hydrochloric acid at 20°C

1g of powdered marble in 100cm3 of hydrochloric acid at 30°C.

1g of powdered marble in 100cm3 of hydrochloric acid at 20°C

The rate of a chemical reaction increases with an increase in temperature. Therefore, the mixture with 1g of powdered marble in 100cm3 of hydrochloric acid at 30°C is likely to have the greatest rate of reaction. The higher temperature provides more energy to the particles, increasing their kinetic energy and collision frequency, leading to a faster reaction. The smaller particle size of the powdered marble also increases the surface area available for reaction, further enhancing the rate of reaction.

Explanation

The rate of a chemical reaction increases with an increase in temperature. Therefore, the mixture with 1g of powdered marble in 100cm3 of hydrochloric acid at 30°C is likely to have the greatest rate of reaction. The higher temperature provides more energy to the particles, increasing their kinetic energy and collision frequency, leading to a faster reaction. The smaller particle size of the powdered marble also increases the surface area available for reaction, further enhancing the rate of reaction.

3. Which of the following statements about collisions is correct?

All colliding particles have the same amount of energy

Only fast-moving particles collide with each other

Reactions can happen if the colliding particles have enough energy

The correct answer is "Reactions can happen if the colliding particles have enough energy." This statement is correct because for a reaction to occur, the colliding particles must possess enough energy to overcome the activation energy barrier. If the particles have sufficient energy, they can break the existing bonds and form new ones, resulting in a chemical reaction. This statement implies that not all colliding particles have the same amount of energy and that even slow-moving particles can collide and react if they have enough energy.

Explanation

The correct answer is "Reactions can happen if the colliding particles have enough energy." This statement is correct because for a reaction to occur, the colliding particles must possess enough energy to overcome the activation energy barrier. If the particles have sufficient energy, they can break the existing bonds and form new ones, resulting in a chemical reaction. This statement implies that not all colliding particles have the same amount of energy and that even slow-moving particles can collide and react if they have enough energy.

4. In each of four different experiments, the same mass of magnesium reacts with the same volume of excess sulfuric acid. Which set of conditions will result in the magnesium being used up the fastest?

Ribbon magnesium, 1 mol/dm3 of acid, 80 degrees celsius

Powdered magnesium, 0.5 mol/dm3 of acid, 20 degrees celsius

Ribbon magnesium, 0.5 mol/dm3 of acid, 80 degrees celsius

Powdered magnesium, 1 mol/dm3 of acid, 80 degrees celsius

The powdered magnesium will react faster because it has a larger surface area compared to the ribbon magnesium. This allows for more contact between the magnesium and the acid, increasing the rate of reaction. Additionally, increasing the concentration of the acid to 1 mol/dm3 and raising the temperature to 80 degrees celsius both increase the rate of reaction according to the collision theory.

Explanation

The powdered magnesium will react faster because it has a larger surface area compared to the ribbon magnesium. This allows for more contact between the magnesium and the acid, increasing the rate of reaction. Additionally, increasing the concentration of the acid to 1 mol/dm3 and raising the temperature to 80 degrees celsius both increase the rate of reaction according to the collision theory.

5. Reactions eventually stop. What is generally the reason for this?

The catalyst has been used up

The particles have run out of energy

One or more of the reactants has been used up.

Reactions eventually stop because one or more of the reactants has been used up. When a reactant is completely consumed, the reaction can no longer proceed as there are no more molecules available for the reaction to occur. This depletion of reactants leads to the cessation of the reaction.

Explanation

Reactions eventually stop because one or more of the reactants has been used up. When a reactant is completely consumed, the reaction can no longer proceed as there are no more molecules available for the reaction to occur. This depletion of reactants leads to the cessation of the reaction.

6. When an excess of calcium carbonate reacts with dilute hydrochloric acid, the reaction becomes slower and finally stops because

The calcium carbonate is covered by bubbles of carbon dioxide

An insoluble layer of calcium chloride is formed

The calcium carbonate is all used up

The hydrochloric acid is all used up

The correct answer is that the hydrochloric acid is all used up. In this reaction, calcium carbonate reacts with hydrochloric acid to form calcium chloride, carbon dioxide, and water. As the reaction proceeds, the hydrochloric acid is gradually consumed, resulting in a decrease in the concentration of the acid. Eventually, all the hydrochloric acid is exhausted, causing the reaction to slow down and eventually stop.

Explanation

The correct answer is that the hydrochloric acid is all used up. In this reaction, calcium carbonate reacts with hydrochloric acid to form calcium chloride, carbon dioxide, and water. As the reaction proceeds, the hydrochloric acid is gradually consumed, resulting in a decrease in the concentration of the acid. Eventually, all the hydrochloric acid is exhausted, causing the reaction to slow down and eventually stop.