Question

(d) the compound k₂o₂ also exists. a chemist can determine the mass of k in a sample of known mass that consists of either pure k₂o or pure k₂o₂. from this information, can the chemist answer the question of which compound is in the sample? indicate yes or no, and explain.

Explanation:

The mass - percentage of potassium ($K$) is different in $K_2O$ and $K_2O_2$. Calculate the mass - percentage of $K$ in each compound using molar masses. For $K_2O$, molar mass of $K_2O=(2\times39.10)+16.00 = 94.20\ g/mol$, mass - percentage of $K=\frac{2\times39.10}{94.20}\times100\%\approx83.0\%$. For $K_2O_2$, molar mass of $K_2O_2=(2\times39.10)+(2\times16.00)=110.20\ g/mol$, mass - percentage of $K=\frac{2\times39.10}{110.20}\times100\%\approx70.2\%$. By knowing the mass of $K$ in a sample of known total mass, the chemist can calculate the mass - percentage of $K$ in the sample and compare it with the calculated mass - percentages for $K_2O$ and $K_2O_2$ to identify the compound.

Answer:

Yes