Suggest a reason the reaction between manganese carbonate and dilute hydrochloric acid speeds up when some concentrated hydrochloric acid is added.

In two separate experiments, two metals $\mathrm{A}$ and $\mathrm{B}$ were reacted with an excess of dilute hydrochloric acid. The volume of hydrogen was measured every $10$ seconds. These graphs show the results:

Which piece of apparatus can be used to measure the volume of hydrogen produced?

In two separate experiments, two metals $\mathrm{A}$ and $\mathrm{B}$ were reacted with an excess of dilute hydrochloric acid. The volume of hydrogen was measured every $10$ seconds. These graphs show the results:

What measuring equipment is needed other than gas syringe?

In two separate experiments, two metals $\mathrm{A}$ and $\mathrm{B}$ were reacted with an excess of dilute hydrochloric acid. The volume of hydrogen was measured every $10$ seconds. These graphs show the results:

Which metal, $\mathrm{A}$ and $\mathrm{B}$, reacts faster with hydrochloric acid? Give your evidence.

IN two separate experiments, two metals $\mathrm{A}$ and $\mathrm{B}$ were reacted with an excess of dilute hydrochloric acid. The volume of hydrogen was measured every $10$ seconds. These graphs shows the results:

Sketch and label the curves that will be obtained for metal $\mathrm{B}$ if more concentrated acid is used (curve $\mathrm{X}$).

IN two separate experiments, two metals $\mathrm{A}$ and $\mathrm{B}$ were reacted with an excess of dilute hydrochloric acid. The volume of hydrogen was measured every $10$ seconds. These graphs shows the results:

Sketch and label the curves that will be obtained for metal $\mathrm{B}$ if the reaction is carried out at a lower temperature (curve $\mathrm{Y}$).

Copper(II) oxide catalyses the decomposition of hydrogen peroxide. $0.5 \mathrm{g}$ of the oxide was added to a flask containing $100 {\mathrm{cm}}^3$ of hydrogen peroxide solution. A gas was releases. It was collected, and its volume noted every $10$ seconds. This table shows the results:

What is a catalyst?

Copper(II) oxide catalyses the decomposition of hydrogen peroxide. $0.5 \mathrm{g}$ of the oxide was added to a flask containing $100 {\mathrm{cm}}^3$ of hydrogen peroxide solution. A gas was releases. It was collected, and its volume noted every $10$ seconds. This table shows the results:

Draw a diagram of suitable apparatus for this experiment.