Question

A pure gold (24k) has a density of 19.32g/cm3. A wedding band weighs 3.50 grams. How much water must it displace (i.e what must its volume be?) if the band is in fact 24k gold?

Answer 1

24k (k for karats) gold is a really pure one and it means that the band is made of a pure metal, which was quite strange for me. I never saw a band made of the pure gold. However, the volume, mass and density are all interrelated to each other as the following expression:

$V(gold)=\frac{m(gold)}{d(gold)}$

Thus,

$V(gold)=\frac{3.50g}{19.32g/cm^3}=0.181cm^3$

We can also say that it is 0.181 mL or 1.81*10^-4 L of possibly displaced water (when the band will be sank in water).

P.S. The jewelry gold metal is always a complicated alloy of gold, silver, nickel and copper.