You add 8.7g of iron to 21.30mL of water and observe that the volume of iron and water together is 22.41mL . Calculate the density of iron.

Answer 1

22.41 - 21.30 = 1.11 mL
so
8.7 g/1.11 mL = 7.838 g/mL or g/cm^3

almost 8 times density of water by the way which is how you remember it.