Question

Aluminum has a density of 2.70 g/mL2.70 g/mL. Calculate the mass (in grams) of a piece of aluminum having a volume of 267 mLmL .

Express your answer to three significant figures.

Iron has a density of 7.86 g/cm37.86 g/cm3 (1 cm3=1 mL1 cm3=1 mL). Calculate the volume (in dLdL) of a piece of iron having a mass of 4.94 kgkg . Note that the density is provided in different units of volume and mass than the desired units of volume (dLdL) and the given units of mass (kgkg). You will need to express the density in kg/dLkg/dL (1 cm3 = 1 mL1 cm3 = 1 mL) before calculating the volume for the piece of iron.

Express your answer to three significant figures.

Answer 1

the density of a substances tells you the mass of exactly one unit of volume of substances

in this case aluminium is said to have a density of = 2.70 g/ml

this tells you every 1 ml of aluminium has a mass of 2.70 g

all we have to now is use the density of aluminium as a conversion factor to go from ml to aluminium to grams

=> 267 ml . (2.70 g / 1 ml) = 720.9 g

=> 721 g

similarly

for iron has a density = 7.86 g/cm³ = 0.789 kg/dL

given mass = 4.94 kg

volume of piece of iron = given mass / density

= 4.94 kg / 0.789 kg/dL

= 6.26 dL