Chemistry Conversion

Question

A mouthwash is 21.6% ethyl alcohol by mass. If each bottle contains 0.358 pt of mouthwash with a density of 0.876 g/mL, how many kilograms of ethyl alcohol are in 164 bottles of the mouthwash?
Express your answer with the appropriate units.

Answer 1

First, convert pts to mls in order to work in same units as density.

1 pt = 473.176 mls

Converting 0.358 pts to mls:  0.358 pts x 473.176 mls/pt =169.397 mls in each bottle

Converting this to grams:  169.397 mls x 0.876 g/ml = 148.39 grams in each bottle

Calculating mass of ethyl alcohol in each bottle:  148.39 g x 0.216 = 32.05 g ethyl alcohol in each bottle

Calculating mass of ethyl alcohol in 164 bottles:  32.05 g/bottle x 164 bottles = 5256.6 g

Converting this mass to kg:  5256.6 g x 1 kg/1000 g = 5.257 kg

Expressing answer with correct number of significant figures:  5.26 kg