Question

The density lead is 11.3 g/mL. What is the mass of 45 mL of the of metal?

Answer 1

`"510 g"`

Explanation:

For a sample of a substance, the relationship between the mass of the sample and the volume it occupies is given by the density of the substance.

The density of a substance tells you the mass of exactly one unit of volume. In your case, the density of lead is given in `"g mL"^(-1)`, which makes your unit of volume equal to `"1 mL"`.

A density of `"11.3 g mL"^(-1)` means that every unit of volume, i.e. every milliliter, of lead has a mass of `"11.3 g"`.

You know that your sample occupies `"45 mL"`, which implies that it must have a mass of

`45 color(red)(cancel(color(black)("mL"))) * color(white)(overbrace(color(black)("11.3 g"/(1color(red)(cancel(color(black)("mL"))))))^(color(blue)("the density of lead"))) = color(green)(|bar(ul(color(white)(a/a)color(black)("510 g")color(white)(a/a)|)))`

The answer is rounded to two sig figs.