The problem A bubble of kryptopn (Kr) gas is formed underwater. The bubble has a volume of 2.14x10-6m3 and contains 1.70x1020 krypton molecules each of mass 1.39x10-25kg. The pressure of the gas inside the bubble is 300kPa. Calculate the relative molecular mass. The attempt at a solution When i looked in the markscheme of this paper, the answer was Mr=1.39x10-25/1.66x10-27 as the answer. so does this mean to find the relative molecular mass i divide the mass by the unified mass unit?