Question #8d973

1 Answer
Sep 1, 2017

Answer:

#"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_"Fe" = "7.874 g cm"^(-3) -># source
  • #rho_"Al" = "2.70 g cm"^(-3) -># 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 #"1 cm"^3# of iron has a mass of #"7.784 g"# and #"1 cm"^3# of aluminium has a mass of #"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, #"75 cm"^3# of iron will have a greater mass than #"100 cm"^3# of aluminium.