# If an Alka-Seltzer tablet contained 309 mg of aspirin, 1.927 xx 10^03 mg of sodium hydrogen carbonate, and 1.004 xx 10^03mg of citric acid and nothing else, what is the percent, by mass, of sodium hydrogen carbonate in the tablet?

Oct 1, 2016

The percent composition of sodium hydrogen carbonate $\left(\text{NaHCO"_3}\right)$ in the Alka-Seltzer tablet is 59.5%.

#### Explanation:

Percent composition is determined by dividing the mass of the specified compound by the total mass, then multiply by 100.

$\text{Percent composition"="mass of specified component"/"total mass"xx100}$

Add the masses of the compounds.

("309 mg")+(1.927xx10^3 "mg")+(1.004xx10^3"mg")=3.24xx10^3 "mg"

Divide the mass of sodium hydrogen carbonate $\text{NaHCO"_3}$ by the total mass of the tablet, then multiply by 100.

$\text{Percent composition of NaHCO"_3=(1.927xx10^3"mg HCO"_3)/(3.24xx10^3"mg")xx100="59.5% NaHCO"_3}$