# Can someone please solve this three questions for me. Thank you for your help. (1)- in an experiment, 5g of copper was heated with excess sulphur yield 3g of copper (1)sulphide. what is the percentage yield?

30%

#### Explanation:

Mass: S= 32g , Cu= 63.5g ... $C {u}_{2} S$=127g

practical product = 3g of $C {u}_{2} S$

$2 C u + S \to C {u}_{2} S$

63.5g --- 127g
$\textcolor{w h i t e}{d}$ 5g$\textcolor{w h i t e}{d}$ --- x

$\frac{\text{127 * 5}}{63.5} = 10 g$ --> theoretical product

Percentage yield:

$\text{practical product"/"theoretical product} \cdot 100$

"3g"/"10g"*100=30%