Question

Calculate the value of following expression.
$M\left(H_2\right)\times (M\left(O_2\right)/M\left(H_{2}O\right))$
Given:
$M\left(H_2\right)$ = moles in 24 g $H_2$
$M\left(O_2\right)$ = moles in 80 g $O_2$
$M\left(H_{2}O\right)$ = moles in 72 g $H_{2}O$

• A. $5$
• B. $7.5$
• C. $10$
• D. $12.5$

Answer 1

The correct option is B $7.5$

Moles of $H_2$ $=24/2=12$
Moles of $O_2$ $=80/32=2.5$
Moles of $H_{2}O$ $=72/18=4$
Therefore, the expression has a value of $12\times \frac{2.5}{4}=7.5$