The graph shows how the total volume of a gas given off from a reaction changes with time. In which time interval is least gas given off?

• A

• B

• C

• D

An experiment with a reaction mixture of carbonate and acid in a container was placed on an electronic balance. The mass of reactants and container was measured at regular time intervals. A graph of the mass reading against time was plotted. Which curve was obtained?

• A

• B

• C

• D

Graph E represents the rate of volume of gas formed from the original experiment. Which graph best represents the same experiment conducted at a lower temperature?

• W

• X

• Y

• Z

In an experiment, a 2 g lump of zinc and 2 g of powdered zinc are added separately to equal volumes of dilute sulfuric acid.The solid line on the graph shows the volume of gas given off when the 2 g lump is used.

Which dotted line is obtained when the zinc is powdered?

• A

• B

• C

• D

• A

• B

• C

• D

In an experiment, a 2 g of powdered zinc are added separately to two samples of equal volumes of dilute sulfuric acid and hydrochloric acid of the same concentration. The solid line on the graph shows the volume of gas given off when sulfuric acid is used. Excess zinc powder is used.

Which dotted line is obtained when the hydrochloric acid is used?

• A

• B

• C

• D

In an experiment, powdered calcium carbonate are added separately to two samples of equal volumes of dilute sulfuric acid of 1.0 mol/dm³ and 2.0 mol/dm³. The solid line on the graph shows the volume of gas given off when 1.0 mol/dm³ sulfuric acid is used. Acid is in excess.

Which dotted line is obtained when the 2.0 mol/dm³ sulfuric acid is used?

• A

• B

• C

• D

An experiment was conducted for the reaction below between excess calcium carbonate and 100.0 cm³ of hydrochloric acid.

CaCO₃(s) + 2HCl (aq) → 2CaCl₂(aq) + H₂O(l) + CO₂(g)

Which factor(s) would cause a greater decrease in mass?

• Conducting the reaction at a higher temperature

• Using the same volume of HCl but with a higher concentration

• Sealing the flask

Examine the graph for an experiment involving the collection of a carbon dioxide over time. Trials I and II were for the same reaction, but under different conditions.

Calculate the average rate of reaction, in cm³ s⁻¹, for Trial I for the first 5 seconds of the reaction. Give the answer to one significant figure and units are not required in the answer. 

Identify which of the following units would not be appropriate for expressing the rate of a reaction.

• cm³ s

• g s^–1

• mol dm^–3 s^–1

• kPa min^–1