Question

Percentage of calcium in calcium nitrate is:

• A. $48\%$
• B. $40\%$
• C. $28\%$
• D. $24\%$

Answer 1

The correct option is D $24\%$

The formula of calcium carbonate is $Ca(N{O}_3{)}_2$.
Atomic mass of $Ca=40\text{amu}$
Molecular mass of $Ca(N{O}_3{)}_2=40+2\times (14+3\times 16)=164\text{amu}$
The percentage of calcium would be:
$=\frac{\text{Mass of Calcium}}{\text{Mass of Calcium nitrate}}\times 100=\frac{40}{164}\times 100\approx 24\%$