What volume of gas, in cm³, would be obtained by reaction between 100 cm³ of ammonia gas and excess copper(II) oxide? All volumes are measured at atmospheric pressure and 20°C. - Scottish Highers Chemistry - Question 14 - 2018

The balanced chemical equation is:

$3 \text{CuO} + 2 \text{NH}_3 \rightarrow 3 \text{Cu} + \text{N}_2 + 3 \text{H}_2O$

From the reaction, 2 volumes of ammonia (NH₃) yield 1 volume of nitrogen (N₂). Therefore, 100 cm³ of ammonia will yield:

$\text{Volume of } N_2 = \frac{100 \text{ cm}^3}{2} = 50 \text{ cm}^3$