Question

what mass of water is formed when 2 moles of hydrogen react with 1 mole of oxygen to form water?A. 2 gB. 18.01C. 36.02 D. 9 g

Answer 1

C. 36.02

Step-by-step explanation

Given:

Moles of hydrogen that reacts = 2 mol

Moles of oxygen that reacts = 1 mol

What to find:

The mass of water formed when the moles of hydrogen and oxygen above react.

Solution:

The first step is to write a balanced chemical equation for the reaction to know the mole ratio of H to O

`2H_2+O_2\rightarrow2H_2O`

The mole ratio of hydrogen to water in the balanced equation is 2:2

The next step is to calculate the mole of water produced from the given moles of H and O using the mole ratio.

`\begin{gathered} 2mol\text{ }H_2=2mol\text{ }H_2O \\ \\ 2mol\text{ }H_2=x \\ \\ x=\frac{2mol\text{ }H_2}{2mol\text{ }H_2}*2mol\text{ }H_2O \\ \\ x=2mol\text{ }H_2O \end{gathered}`

The final step is to convert the 2 moles of water produced to mass in grams using the molar mass of water and mole formula.

The molar mass of water = 18.01g/mol

`\begin{gathered} Moles=\frac{Mass}{Molar\text{ }mass} \\ \\ Mass=Moles* Molar\text{ }mass \\ \\ Mass=2mol*18.01g\text{/}mol \\ \\ Mass=36.02\text{ }g \end{gathered}`

Hence, the mass of water formed is 36.02 g.

The answer is C. 36.02