What is the density of a substance that has a mass of 112 g and a volume of 53 mL?

2 Answers
Jun 10, 2017

"Density", rho~=2*g*mL^-1

Explanation:

By definition, rho="Mass of substance"/"Volume of substance".

Here, we are given the mass and the volume with respective units of "grams" and "millilitres", and we can thus directly assess the quotient without pfaffing about with units.........

rho_"substance"=(112*g)/(53*mL)=??*g*mL^-1.

Would this substance float? Why or why not?

Jun 10, 2017

"2.1 g mL"^(-1)

Explanation:

Density is simply a measure of the mass of exactly one unit of volume of a given substance.

In this case, your sample is said to occupy a volume of "53 mL", which means that one unit of volume is "1 mL". This implies that in order to find the density of the unknown substance, you must figure out the mass of "1 mL".

You already know that "53 mL" have a mass of "112 g", so set up the equation like this

overbrace((color(blue)(?)color(white)(.)"g")/"1 mL")^(color(red)("the density of the substance")) = overbrace("112 g"/"53 mL")^(color(red)("its known composition"))

Rearrange and solve to find

color(blue)(?) = (1 color(red)(cancel(color(black)("mL"))))/(53color(red)(cancel(color(black)("mL")))) * "112 g"

color(blue)(?) ="2.1 g"

So, if "1 mL" of this substance has a mass of "2.1 g", you can say that its density is equal to

color(darkgreen)(ul(color(black)("density = 2.1 g mL"^(-1))))

The answer is rounded to two sig figs, the number of sig figs you have for the volume of the sample.