# A sample of C25H52 weighs 29.29 g. Its molar mass is 352.77g/mol. How many grams of carbon are in this sample?

## Any help is much appreciated!

Jan 24, 2017

$24.93 g$, rounded to two decimal places.

#### Explanation:

Given is sample of ${\text{C"_25"H}}_{52}$

We see that $1 \text{ g mol}$ of sample has $25$ carbon atoms

Taking Average atomic mass of carbon $\text{C"=12.011" amu}$, we obtain gram molecular weight of carbon in 1 mol of sample$= 25 \times 12.011$
$= 300.275$
Setting up the equation

$352.77 g$ of sample has carbon$= 300.275 g$
$1 g$ of sample has carbon$= \frac{300.275}{352.77} g$
$29.29 g$ of sample has carbon$= \frac{300.275}{352.77} \times 29.29$
$= 24.93 g$, rounded to two decimal places.

Jan 24, 2017

Approx. $25 \cdot g$
%"by mass of carbon with respect to 1 mole of "C_25H_52 $=$ (25xx12.011*g*mol^-1)/(352.77*g*mol^-1)xx100%=85.12%
And thus, in a $29.29 \cdot g$ mass, %C=29.29*gxx85.12%=??