Chapter 3, Problem 80A

Interpretation Introduction

Interpretation:

The given table needs to be completed.

Concept introduction:

The mass percent of an atom in any compound is found as:

$\mathrm{mass}\%oftheelement=\frac{massoftheelement}{totalmassofcomp.}\times 100$

Answer to Problem 80A

The $\mathrm{mass}\%ofO$ and the mass of second element in the different compounds are:

In $\mathrm{CuO}$ it is $20\%$ and $64\mathrm{gm}$.

In ${\mathrm{H}}_{2}O$ it is $88\%$ and $2\mathrm{gm}$.

In ${\mathrm{H}}_2{O}_2$ it is $94\%$ and $2\mathrm{gm}$.

In $CO$ it is $57\%$ and $12\mathrm{gm}$.

In $C{O}_2$ it is $73\%$ and $12\mathrm{gm}$.

Explanation of Solution

$\mathrm{mass}\%ofO=\frac{massofO}{totalmassofcomp.}\times 100$

1. For $\mathrm{CuO}$

$\mathrm{mass}\%ofO=\frac{16}{80}\times 100=20\%$

Mass of second element in the compound is $80-16=64\mathrm{gm}$.

2. For ${\mathrm{H}}_{2}O$

$\mathrm{mass}\%ofO=\frac{16}{18}\times 100=88\%$

Mass of second element in the compound is $18-16=2\mathrm{gm}$.

3. For ${\mathrm{H}}_2{O}_2$

$\mathrm{mass}\%ofO=\frac{32}{34}\times 100=94\%$

Mass of second element in the compound is $34-32=2\mathrm{gm}$.

4. For $CO$

$\mathrm{mass}\%ofO=\frac{16}{28}\times 100=57\%$

Mass of second element in the compound is $28-16=12\mathrm{gm}$.

5. For $C{O}_2$

   $\mathrm{mass}\%ofO=\frac{32}{44}\times 100=73\%$

   Mass of second element in the compound is $44-32=12\mathrm{gm}$ .

Conclusion

The different mass percentage and the masses of second compound are calculated as:

In $\mathrm{CuO}$ it is $0.2\%$ and $64\mathrm{gm}$.

In ${\mathrm{H}}_{2}O$ it is $0.88\%$ and $2\mathrm{gm}$.

In ${\mathrm{H}}_2{O}_2$ it is $0.94\%$ and $2\mathrm{gm}$.

In $CO$ it is $0.57\%$ and $12\mathrm{gm}$.

In $C{O}_2$ it is $0.73\%$ and $12\mathrm{gm}$.