Question #819ef

1 Answer
Dec 19, 2017

Answer:

#"3.2 g cm"^(-3)#

Explanation:

The density of a material is simply the mass of exactly one unit of volume of that material.

In this case, you know that a #"25-cm"^3# volume of this material has a mass of #"81 g"#, so in order to find its density, you must use this information to figure out the mass of #"1 cm"^3# of this material.

You can set up a conversion factor that has the mass of the sample as the numerator and the volume it occupies as the denominator.

You will have

#1 color(red)(cancel(color(black)("cm"^3))) * "81 g"/(25color(red)(cancel(color(black)("cm"^3)))) = "3.24 g"#

So, if #"1 cm"^3# of this material has a mass of #"3.24 g"#, you can say that the density of the material is equal to

#color(darkgreen)(ul(color(black)("density"))) = "3.24 g cm"^(-3) ~~ color(darkgreen)(ul(color(black)("3.2 g cm"^(-3))))#

The answer must be rounded to two sig figs, the number of sig figs you have for your values.