Pure rubber gum has a density of approx 0.91 to 0.93 grams per mL.
Generally, the density of rubber is 1.2 .
A rubber stopper has a mass of 14 grams and a volume of 7 cm3. To solve for density, take mass divided by volume. 14g / 7 cm3 = 2 g/cm3.
Some hard rubber has a density of 1.2
Rubber floats in water because the density of rubber is less than the density of water.
Osmium has a density of 22.61 grams. Iridium has a density of 22.56 grams. Mercury has a density of 13.6 grams.
about 11-12 grams of rubber
The density is simply 10 grams per litre. The bit about "a mass of 50 grams" is irrelevant to the calculation of density.