# What is the mass in grams of 0.750 moles of C_3H_8?

Aug 26, 2017

Well what is the mass of one mole of propane.....?

#### Explanation:

Well, it's $44.1 \cdot g$, and how did we get this?

We take the sum....$3 \times 12.011 \cdot g \cdot m o {l}^{-} 1 \left(C\right) + 8 \times 1.00794 \cdot g \cdot m o {l}^{-} 1 \left(H\right)$; from where did I get the atomic masses? Did I know them off the top of my head? Do you have to learn them?

We have got a $0.750 \cdot m o l$ quantity, and to get its mass we take the product......

$0.750 \cdot m o l \times 44.1 \cdot g \cdot m o {l}^{-} 1 \cong 30 \cdot g$