Density Problems Help?

Question

A cube of air that measures 1.2 x 10^-4 cm by 8.34 x 10^-3 mm by 6.0 x 10^-6 dm has density of .00118 g/cm^3. Find its mass in grams.

Answer 1

1.2 x 10^-4 cm

by 8.34 x 10^-3 mm (aka 8.34e-4 cm)

by 6.0 x 10^-6 dm  (aka 6.0e-5 cm)

volume =

(1.2e-4 cm) ( 8.34e-4 cm) (6.0e-5 cm) = 6.005e-12 cm3

mass=

6.005e-12 cm3 @ 0.00118 g/cm^3 = 7.09e-15 grams

your answer (2 sigfigs) = 7.1e-15 grams