Respuesta :
Answer: The percent by mass of perchloric acid in the mixture is 22.92 %.
Explanation:
- To calculate the moles of a solute, we use the equation:
[tex]\text{Molarity of the solution}=\frac{\text{Moles of solute}}{\text{Volume of solution (in L)}}[/tex]
We are given:
Volume of potassium hydroxide = 20.4mL = 0.0204 L (Conversion factor: 1 L = 1000 mL)
Molarity of the solution = 0.922 moles/ L
Putting values in above equation, we get:
[tex]0.922mol/L=\frac{\text{Moles of potassium hydroxide}}{0.0204L}\\\\\text{Moles of potassium hydroxide}=0.0188mol[/tex]
- For the given chemical reaction:
[tex]HClO_4+KOH\rightarrow KClO_4+H_2O[/tex]
By Stoichiometry of the reaction:
1 mole of potassium hydroxide reacts with 1 mole of perchloric acid.
So, 0.0188 moles of potassium hydroxide will react with = [tex]\frac{1}{1}\times 0.0188=0.0188mol[/tex] of perchloric acid.
- To calculate the mass of perchloric acid, we use the equation:
[tex]\text{Number of moles}=\frac{\text{Given mass}}{\text{Molar mass}}[/tex]
Moles of perchloric acid = 0.0188 moles
Molar mass of perchloric acid = 100.46 g/mol
Putting values in above equation, we get:
[tex]0.0188mol=\frac{\text{Mass of perchloric acid}}{100.46g/mol}\\\\\text{Mass of perchloric acid}=1.88g[/tex]
- To calculate the percent by mass of perchloric acid, we use the equation:
[tex]\text{Mass percent}=\frac{\text{Mass of the solute}}{\text{Mass of solution}}\times 100[/tex]
We are given:
Mass of perchloric acid = 1.88 g
Mass of solution = 8.20 g
Putting values in above equation, we get:
[tex]\text{Mass percent of perchloric acid}=\frac{1.88g}{8.20g}\times 100\\\\\text{Mass percent of perchloric acid}=22.92\%[/tex]
Hence, the percent by mass of perchloric acid in the mixture is 22.92 %.
