# Question 8d973

Sep 1, 2017

${\text{75 cm}}^{3}$ of iron.

#### Explanation:

Your tools of choice here will be the densities of the two elements, which you'll find listed as

• ${\rho}_{\text{Fe" = "7.874 g cm}}^{- 3} \to$ source
• ${\rho}_{\text{Al" = "2.70 g cm}}^{- 3} \to$ source

Keep in mind that the two densities are cited for room temperature, which implies that you're dealing with solid iron and solid aluminium.

Now, the density of a substance tells you the mass of exactly $1$ unit of volume that substance occupies.

In your case, you know that ${\text{1 cm}}^{3}$ of iron has a mass of $\text{7.784 g}$ and ${\text{1 cm}}^{3}$ of aluminium has a mass of $\text{2.70 g}$.

This means that your two samples will have masses of

75 color(red)(cancel(color(black)("cm"^3))) * overbrace("7.784 g"/(1color(red)(cancel(color(black)("cm"^3)))))^(color(blue)("the density of iron")) = "584 g"

100color(red)(cancel(color(black)("cm"^3))) * overbrace("2.70 g"/(1color(red)(cancel(color(black)("cm"^3)))))^(color(blue)("the density of aluminium")) = "270 g"#

As you can see, ${\text{75 cm}}^{3}$ of iron will have a greater mass than ${\text{100 cm}}^{3}$ of aluminium.