Q20P - Chemistry: Molecular Nature Of Matter And Change

Question

Calculate each of the following:

1. Mass fraction of C in cesium acetate
2. Mass fraction of O in uranyl sulfate trihydrate $\mathit{U}{\mathit{O}}_{\mathbf{2}}^{\mathbf{2}\mathbf{+}}$

Step-by-Step Solution

Answer

1. Mass fraction of C is 0.125
2. Mass fraction of O is 0.343

Step 1: Definition of Mass

A property that reflects the quantity of matter within a sample is defined as mass

Step 2: Calculations of mass fraction of C in cesium acetate

The molar mass of cesium acetate is $\mathbf{191}\mathbf{.}\mathbf{96}\frac{\mathbf{g}}{\mathbf{mol}}$

Mass fraction of C$\mathbf{=}\frac{\mathbf{2}\mathbf{molC}\left({\displaystyle \frac{12.01\mathrm{gC}}{\mathrm{mol} C}}\right)}{\mathbf{191}\mathbf{.}\mathbf{96}\mathbf{g}\mathbf{ }{\mathbf{CH}}_{\mathbf{3}}{\mathbf{CO}}_{\mathbf{2}}\mathbf{Cs}}$

Mass fraction of C is 0.125.

Step 3: Determination of mass fraction of O in uranyl sulfate trihydrate

The molar mass of uranyl sulfate trihydrate is $\mathbf{420}\mathbf{.}\mathbf{16}\frac{\mathbf{g}}{\mathbf{mol}}$

Mass fraction of O $\mathrm{O}\mathbf{=}\frac{\mathbf{9}\mathbf{ }\mathbf{molO}\left({\displaystyle \frac{16.00g O}{\mathrm{mol} O}}\right)}{\mathbf{420}\mathbf{.}\mathbf{16}\mathbf{g}\mathbf{ }{\mathbf{UO}}_{\mathbf{2}}{\mathbf{SO}}_{\mathbf{4}}\mathbf{.}\mathbf{3}{\mathbf{H}}_{\mathbf{2}}\mathbf{O}}$

Mass fraction of O is 0.343.