Question

Calculate the mass of water formed when 2.6 moles of hydrogen reacts with excess oxygen gas.

2H2+O2>2H2O

Answer 1

2.6 moles of hydrogen produces 2.6 mol of water

so

$2.6=\dfrac{\text{ Mass of } H_2O}{\text{ Molar mass}} \\[9pt] 2.6=\dfrac{x}{18}\Rightarrow x=45g$

Hence The mass of the water formed is 45 g.