Question

The mass unit associated with density is usually grams. if the volume (in ml or cm3) is multiplied by the density (g/ml or g/cm3) the volume units will cancel out, leaving only the mass units. keep in mind that the volume and density must use the same volume unit for the cancellation. if a large marshmallow has a volume of 2.00 in3 and density of 0.242 g/cm3, how much would it weigh in grams? 1 in3=16.39 cm3. express your answer in grams to three significant figures.

Answer 1

The weight in grams = 7.93 g

Given volume = 2.00 $in^{3}$

Given  density = 0.242 g/$cm^{3}$

We need to find the Mass(weight) in grams.

To find the weight in grams we need to keep in mind that the volume and density must use the same volume unit for cancellation. So that the volume units will cancel out, leaving only the mass units.

The unit of given volume is $in^{3}$ and unit of volume in density is $cm^{3}$ , so first we need to change the unit of volume from $in^{3}$ to $cm^{3}$ so that the volume units will cancel out, leaving only the mass units.

1 $in^{3}$ = 16.39 $cm^{3}$ (given conversion)

$2 in^{3}\times \frac{(16.39 cm^{3})}{(1 in^{3})}$

$in^{3}$ units get cancel out leaving the $cm^{3}$ unit.

$2 in^{3} = 32.78 cm^{3}$

Mass = Density X Volume.

Density = 0.242 g/$cm^{3}$ and Volume = 32.78 $cm^{3}$

$Mass =0.242\frac{g}{cm^{3}}\times 32.78 cm^{3}$

Mass = 7.93 grams (g)