A aqueous solution of Hydrogen Peroxide has a concentration of . If this entire solution undergoes c — Hydrogen Chemistry Question
Question
A $200\text{ mL}$ aqueous solution of Hydrogen Peroxide has a concentration of $34\text{ g L}^{-1}$. If this entire solution undergoes complete thermal decomposition, what exact mass of oxygen gas ($O_2$) will be liberated?
💡 Solution & Explanation
The concentration is $34\text{ g L}^{-1}$. In $200\text{ mL}$ ($0.2\text{ L}$), the mass of $H_2O_2$ is $34 \times 0.2 = 6.8\text{ g}$. The decomposition equation is $2H_2O_2 \rightarrow 2H_2O + O_2$. Molar mass of $H_2O_2 = 34\text{ g mol}^{-1}$. Two moles ($68\text{ g}$) of $H_2O_2$ yield 1 mole ($32\text{ g}$) of $O_2$. Therefore, $6.8\text{ g}$ of $H_2O_2$ yields $(32 / 68) \times 6.8 = 3.2\text{ g}$ of $O_2$.