You can think about a substance's density as being a conversion factor between mass and volume.
More specifically, a substance's density will tell the mass of that substance that occupies one unit of volume.
In this case, 1,3-cycloheptadiene is said to have a density of
So, you know that every
#69.2 color(red)(cancel(color(black)("mL"))) * overbrace("0.868 g"/(1color(red)(cancel(color(black)("mL")))))^(color(purple)("density")) = color(green)(|bar(ul(color(white)(a/a)"60.1 g"color(white)(a/a)|))) ->#rounded to three sig figs.