Percentage composition of ores
It is useful for scientists to be able to calculate exactly what proportion of any ore is actually the desirable metal.
The example below will show you how to complete this.
Question
Tenorite (Cu2O) is an ore of copper. Given that copper has a mass of 63.5 and oxygen a mass of 16, calculate the percentage by mass of copper in tenorite.
Begin by calculating the formula mass.
The percentage of tenorite that is copper is given by the formula:
\(\% \,of\,copper\,in\,tenorite = \frac{{mass\,of\,copper\,in\,tenorite}}{{formula\,mass\,of\,tenorite}} \times 100\)
\(\begin{array}{l} = \frac{{127}}{{143}} \times 100\\ = 88.9\% \end{array}\)
Tenorite is 88.9% copper.
