What mass of lead (density 11.4 g/cm3) would have an identical volume to 18.9 g of mercury (density 13.6 g/cm3)?

Answer 1

Since density is measured in units of mass divided by volume (in this case grams divided by cubic centimeters), if you divide a given mass by the density, you will get the volume.

For the mercury, (18.9 grams)/(13.6 grams/cm^3) = 1.3897 cm^3 of mercury

To get the mass of lead that would have that same volume, multiply this volume by the density of lead

(1.3897 cm^3)*(11.4 grams/cm^3) = 15.84 grams. Since all of your values are only given to three significant figures, you should round this answer off to 15.8 grams, which also has three significant figures.