Answer
1.38 g/L would be the density of gasoline vapor in the container.
Work Step by Step
1. Step one: find the mass of gasoline a $20^{o}C$ :
m = d x v
m = 0.75g/cm3 x 5.5mL ( 1 cm3 = 1 mL, so
m = 0.75g/mL x 5.5mL
m = 4.125 g
m = 4.13 g
Density of the gasoline gas in the container can be found:
d = $\frac{m}{V}$
we found m to be 4.13 g while volume is the volume of the container, as gasoline gas would take the shape and volume of the container.
d = $\frac{4.13 g}{3.00L}$
d= 1.375 g/L
d = 1.38 g/L
1.38 g/L would be the density of gasoline vapor in the container.
