Chapter 3.4, Problem 21PP

Interpretation Introduction

Interpretation:

The percent by mass of element X in the compound and the percent by mass of element Y needs to be determined.

Concept introduction:

The mass percentage is defined as the percentage of component present in it. The mass percentage of the element is the mass of element divided by the total mass of the compound and multiplied by 100.

$\text{Mass percentage=}\frac{\text{mass}\text{of}\text{element}}{\text{mass}\text{of}\text{total}\text{compound}}\text{×100}$

Answer to Problem 21PP

The percent by mass of element X in the compound is $25\%$ and the percent by mass of element Yin the compound is $\text{75\%}$.

Explanation of Solution

Given information:

The given mass of element X is $\text{3}\text{.5 g}$ and the mass of element Y is $\text{10}\text{.5}\text{g}$.

The mass percentage by mass of hydrogen calculated as-

$\text{Mass percentage=}\frac{\text{mass}\text{of}\text{element}}{\text{mass}\text{of}\text{total}\text{compound}}\text{×100}$

$\text{mass}\text{of}\text{compound XY}=\text{3}\text{.5 g + 10}\text{.5 g = 14}\text{.0 g}$

$\text{pecentage}\text{by mass of element X}=\frac{\text{3}\text{.5 g}}{\text{14}\text{.0 g}}\text{×100}\text{=}\text{25}\text{.0\%}$

$\text{pecentage}\text{by mass of element Y}=\frac{\text{10}\text{.5 g}}{\text{14}\text{.0 g}}\text{×100}\text{=}\text{75}\text{.0\%}$

Conclusion

The percent by mass of element X in the compound $=25\%$

The percent by mass of element Yin the compound $\text{=75\%}$.