Write short answers for the following questions, showing the chemical equations where necessary: a) Identify gas F. b) State one laboratory use of calcium hydroxide solution. c) Identify the white pre

16.

a) Gas F is hydrogen.

b) One laboratory use of the solution formed in the beaker (calcium hydroxide solution) is to test for carbon dioxide gas.

c) The white precipitate is formed due to the reaction of the calcium hydroxide solution with atmospheric carbon dioxide. Calcium hydroxide reacts with carbon dioxide to form insoluble calcium carbonate, which appears as a white precipitate.

$$\text{Ca(OH)}_2(aq) + \text{CO}_2(g) \rightarrow \text{CaCO}_3(s) + \text{H}_2\text{O}(l)$$

17.

a) Liquid X is water ($\text{H}_2\text{O}$).

b) The black solid (copper(II) oxide) changes to a reddish-brown solid (copper metal).

c) The equation for the reaction that took place in tube W is:

$$3\text{CuO}(s) + 2\text{NH}_3(g) \xrightarrow{\text{heat}} 3\text{Cu}(s) + \text{N}_2(g) + 3\text{H}_2\text{O}(g)$$