Answer
The mass of the gasoline sample is 31 g, using two significant figures.
Work Step by Step
1- We know that density, volume , and mass are related through density formula:
d = $\frac{m}{v}$
By multiplying both sides with v we get an identical equation, with this one, that we can use to find mass.
d x v = $\frac{m}{v}$ x v
m = d x v
2- Replace values of density and volume to find the mass.
density is 0.70 $\frac{g}{cm^{3}}$
volume is 43.8 mL or 43.8 $cm^{3}$, because 1 mL = 1 $cm^{3}$
(Note: it is important to always check the units before you replace the values in the formulas.)
m = d x v
m = 0.70 $\frac{g}{cm^{3}}$ x 43.8 $cm^{3}$
m = 30.66 g