Answer:
[tex]\large \boxed{\text{About 3 L}}[/tex]
Explanation:
I assume that you have 7 g of Zn, excess HCl, and a temperature of 25 °C.
We will need a balanced chemical equation with molar masses, so, let's gather all the information in one place.
Mᵣ: 65.38
Zn + 2HCl ⟶ ZnCl₂ + H₂
m/g: 7
(a) Moles of Zn
[tex]\text{Moles of Zn} =\text{7 g Zn} \times \dfrac{\text{1 mol Zn}}{\text{65.38 g Zn}} =\text{0.11 mol Zn}[/tex]
(b) Moles of H₂
The molar ratio is 1 mol H₂:1 mol Fe
[tex]\text{Moles of H$_{2}$}= \text{1.0 mol Zn} \times \dfrac{\text{1 mol H$_{2}$}}{ \text{1 mol Zn}} = \text{0.11 mol H$_{2}$}[/tex]
(c) Volume of H₂
We can use the Ideal Gas Law to calculate the volume of hydrogen.
pV = nRT
[tex]\rm V = \dfrac{nRT}{p}= \dfrac{\text{1.1 mol $\times$ 0.08206 L$\cdot$atm$\cdot$K$^{-1}$mol$^{-1}\times$ 298.15 K}}{\text{ 1 atm}} = \textbf{3 L} \\\\\text{The final volume of the balloon is $\large \boxed{\textbf{about 3 L}} $}[/tex]
