Leaving Cert Chemistry - Rates of Reaction (Ordinary Level)

The rate of a chemical reaction may be defined as
1. the change in concentration of any one of the reactants or products
2. the change in concentration of any one of the products only
3. the change in concentration of any one of the reactants only
4. the time it takes for the reaction to be completed
Which of the following of factors does not affect the rate of a chemical reaction?
1. Particle size
2. Colour of the reactants
3. Nature of the reactants
4. Temperature of the reactants
The diagram shows the apparatus for studying the rate of reaction for the decomposition of hydrogen peroxide. Name the gas labelled X in the syringe.
1. Hydrogen
2. Oxygen
3. Carbon dioxide
4. Water vapour
Which one of the following sets of reactants is most likely to have the slowest rate of reaction?
1. Two covalent compounds in solution.
2. A covalent compound in solution and an ionic substance in solution.
3. Two ionic substances in solution.
4. Two solid ionic substances.
In the diagram shown for measuring the rate of reaction between hydrochloric acid and marble chips, what is the purpose of the cotton wool?
1. To prevent air getting into the conical flask.
2. To prevent hydrogen gas escaping.
3. To prevent the contents of the flask from splashing out.
4. To prevent heat escaping from the flask.
A catalyst that slows down a chemical reaction is known as
1. an enzyme
2. a converter
3. a heterogeneous catalyst
4. an inhibitor
A catalyst which is in the same phase as the reactants is known as
1. a heterogeneous catalyst
2. an autocatalyst
3. a homogeneous catalyst
4. a biological catalyst
Which one of the following equations best describes the experiment to monitor the rate of decomposition of hydrogen peroxide using a catalyst?
The diagram shows the volume of oxygen gas collected over time for the decomposition of hydrogen peroxide. At which point on the graph has the reaction stopped?
1. X
2. Y
3. Z
4. W
A magnesium ribbon is reacted with dilute hydrochloric acid. Which one of the following graphs best describes the relationship between the rate of reaction as the reaction proceeds.
Which one of the following reactions will start with the highest rate?
1. 5 g of limestone chips in 100 mL of 0.1 M HCl at 25ºC.
2. 5 g of limestone chips in 100 mL of 0.1 M HCl at 45ºC.
3. 5 g of limestone powder in 100 mL of 0.1 M HCl at 25ºC.
4. 5 g of limestone powder in 100 mL of 0.1 M HCl at 45ºC.
20 grams of magnesium were placed in a conical flask. Which one of the following solutions, if added, would produce 100 mL of hydrogen gas the fastest?
1. 50 mL of 8 M sulfuric acid
2. 100 mL of 4 M sulfuric acid
3. 200 mL of 2 M sulfuric acid
4. 400 mL of 1 M sulfuric acid
When powdered calcium carbonate is added to a solution of hydrochloric acid, it reacts completely within seconds. When the same mass of calcium carbonate chips are added to a similar amount of hydrochloric acid, the reaction takes several minutes to go to completion. Why?
1. An acid will react faster with a powder.
2. The calcium carbonate chips are less soluble than the powder.
3. There are more impurities in the calcium carbonate chips.
4. The powder has a greater surface area.
Catalysts are used in industry because
1. they increase the yield of the products.
2. they increase the rate at which the products are formed.
3. they lower the temperature at which the reaction can proceed.
4. they remove the products from the reaction mixture as the products form.
A catalyst
1. will be chemically unchanged at the end of a reaction.
2. will have a change in its mass at the end of a chemical reaction.
3. will always react with the reactants in a chemical reaction.
4. must be in the same phase (state of matter) as the reactants.
Which one of the following does a catalyst affect in a chemical reaction?
1. The speed of the reaction.
2. The amount of heat liberated or absorbed during the reaction.
3. The amount of product(s) formed.
4. The amount of reactants needed for the reaction to take place.
In the catalytic converter of a motor-car, which of the following sets of gases are produced?
1. Hydrogen and oxygen.
2. Nitrogen and carbon dioxide.
3. Carbon monoxide and nitrogen oxide.
4. Nitrogen dioxide and oxygen.
In the experiment to monitor the rate of decomposition of hydrogen peroxide using a catalyst, which of the following equations is correct?
If the temperature of a reaction is inceased by 10^oC, the reaction rate will be
1. doubled
2. halved
3. four times faster
4. ten times faster
Which one of the following chemical reactions takes place at the greatest rate?
1. A match burning
2. An egg boiling
3. Paint drying
4. Cement settng
What effect does doubling the concentration of one of the reactants have on the rate of reaction?
1. It increases the rate of reaction.
2. It decreases the rate of reaction.
3. It has no effect.
4. The rate of reaction s halved.
In a reaction between two gases, which one of the following factors will not affect the rate of reaction?
1. The colour of the gases
2. The temperature of the gases
3. The volume of the container that the gases react in
4. The pressure of the gases
If the temperature of a reaction is decreased, what effect will this have on the rate of reaction?
1. The rate of reaction will decrease.
2. The rate of reaction will increase.
3. It will have no effect.
4. The reaction will stop.
Which one of the following would make the most suitable catalyst in the decomposition of hydrogen peroxide (H₂O₂)?
1. Manganese dioxide (MnO₂)
2. Liver
3. Sodium chloride (NaCl)
4. Magnesium oxide (MgO)
Why does the rate of reaction increase when powdered calcium carbonate is used instead of marble chips?
1. There is an increase of the surface area of the calcium carbonate
2. There is an increase of the particle size of the calcium carbonate
3. There is an increase of the concentration of the calcium carbonate
4. The powdered calcium carbonate acts as a catalyst
Which one of the following statements is TRUE about catalysts?
1. They are chemically unchanged at the end of the reaction
2. Their appearance is unchanged at the end of the reaction
3. They are solids
4. They are metals
In homogeneous catalysis
1. the reactants and catalyst are in the same state
2. all of the products are in the same state
3. all reactants are in the same state
4. the catalyst is in a different state to the reactants
Where a reactant acts as the catalyst, this is known as
1. autocatalysis
2. heterogeneous catalysis
3. homogeneous catalysis
4. a catalytic converter
For the reaction between calcium carbonate and dilute hydrochloric acid
CaCO₃ + HCl → CaCl₂ + H₂O + CO₂
which one of the following factors will sped up the reaction?
1. Use smaller pieces of calcium carbonate.(CaCO₃
2. Use more dilute acid.
3. Use a bigger conical flask.
4. Lower the temperature of the hydrochloric acid.

Leaving Cert Chemistry - Rates of Reaction (Ordinary Level)

Multiple Choice Quiz