Question

What quantity of copper oxide will react with 2.80 L of hydrogen at NTP?

• A. 79.5 g
• B. 2 g
• C. 9.9 g
• D. 22.4 g

Answer 1

Answer: (C)

9.9 g

Chemical reaction is:

$CuO\left(s\right)+H_2\left(g\right)\to Cu\left(s\right)+H_{2}O$

Number of moles of gas at STP or NTP, $n_{H_2}=\frac{Volume}{22.4}=\frac{2.8}{22.4}=0.125$

Molar mass of $CuO=63.5+16=79.5g$

1 mol of $H_2$ reacts with 1 mol ($79.5g$) of $CuO$

Therefore $0.125$ mol of $H_2$ reacts with $0.125\times 79.5g=9.9g$ of $CuO$

Option C is correct