A compound is formed when 9.03 g Mg combines completely with 3.48 g N. What is the percent composition of this compound?

Feb 20, 2016

The composition is $\text{72.2 % Mg}$ and $\text{27.8 % N}$ by mass.

Explanation:

The formula for percent composition is

"% by mass" = "mass of a component"/"total mass" × 100 %

You have $\text{9.03 g Mg}$ and $\text{3.48 g N}$, so

$\text{total mass = (9.03 + 3.48) g = 12.51 g}$

"% Mg" = (9.03 color(red)(cancel(color(black)("g"))))/(12.51 color(red)(cancel(color(black)("g")))) × 100 % =72.2 %

"% N" = (3.48 color(red)(cancel(color(black)("g"))))/(12.51 color(red)(cancel(color(black)("g")))) × 100 % = 27.8 %

The composition is $\text{72.2 % Mg}$ and $\text{27.8 % N}$ by mass.