Answer:
[tex]\large \boxed{\text{10.9 g}}[/tex]
Explanation:
We will need a chemical equation with masses and molar masses, so, let's gather all the information in one place.
Mᵣ: 18.02 63.02
3NO₂(g) + H₂O(ℓ) ⟶ 2HNO₃(aq) + NO(g)
m/g: 75.9
You start with the substance for which they give you numbers.
For example, this question gives you the mass of HNO₃ and asks you to find the mass of water.
You start with the mass of HNO₃.
Then you convert mass of HNO₃ ⟶ moles of HNO₃ ⟶ moles of water ⟶ mass of water
(a) Moles of HNO₃
[tex]\text{Moles of HNO}_{3} = \text{75.9 g HNO}_{3}\times \dfrac{\text{1 mol HNO}_{3}}{\text{63.02 g HNO}_{3}}= \text{1.204 mol HNO}_{3}[/tex]
(b) Moles of H₂O
[tex]\text{Moles of H$_{2}$O} = \text{1.204 mol HNO}_{3} \times \dfrac{\text{1 mol H$_{2}$O}}{\text{2 mol HNO}_{3}} = \text{0.6022 mol H$_{2}$O}[/tex]
(c) Mass of H₂O
[tex]\text{Mass of H$_{2}$O} =\text{0.6022 mol H$_{2}$O } \times \dfrac{\text{18.02 g H$_{2}$O }}{\text{1 mol H$_{2}$O }} = \textbf{10.9 g H$_{2}$O }\\\\\text{The reaction requires $\large \boxed{\textbf{10.9 g}}$ of H$_{2}$O }[/tex]
