Question

Hydrogen peroxide decomposes in presence of manganese (iv) oxide to give oxygen gas i). Draw a labelled diagram to show the volume of oxygen gas can be measured. (1mark). ii). Explain how an increase in temperature affects the rate of a chemical reaction. (2marks).

Answer 1

Answer:

Oxygen can be made from hydrogen peroxide, which decomposes slowly to form water and oxygen:

hydrogen peroxide → water + oxygen

2H2O2(aq) → 2H2O(l) + O2(g)

The rate of reaction can be increased using a catalyst, manganese(IV) oxide. When manganese(IV) oxide is added to hydrogen peroxide, bubbles of oxygen are given off.

Apparatus arranged to measure the volume of gas in a reaction. Reaction mixture is in a flask and gas travels out through a pipe in the top and down into a trough of water. It then bubbles up through a beehive shelf into an upturned glass jar filled with water. The gas collects at the top of the jar, forcing water out into the trough below.

To make oxygen in the laboratory, hydrogen peroxide is poured into a conical flask containing some manganese(IV) oxide. The gas produced is collected in an upside-down gas jar filled with water. As the oxygen collects in the top of the gas jar, it pushes the water out.

Instead of the gas jar and water bath, a gas syringe could be used to collect the oxygen