Question

What mass of water will be collected if 20.0
grams of hydrogen are consumed
2H2+O2--->2H2O
358g
179g
44.7g
Or 89.4g

Answer 1

Answer: 179 of $H_2O$ will be produced.

Explanation:

To calculate the moles :

$\text{Moles of solute}=\frac{\text{given mass}}{\text{Molar Mass}}$    

$\text{Moles of} H_2=\frac{20.0g}{2.01g/mol}=9.95moles$

$2H_2+O_2(g)\rightarrow 2H_2O$

According to stoichiometry :

2 moles of $H_2$ give =  2 moles of $H_2O$

Thus 9.95 moles of $H_2$ will require=$\frac{2}{2}\times 9.95=9.95moles$  of $H_2O$

Mass of $H_2O=moles\times {\text {Molar mass}}=9.95moles\times 18g/mol=179g$

Thus 179 of $H_2O$ will be produced.