# Co49Ni21Ga30 - molar mass and density

I need to calculate the molar mass and density of the shape memory alloy $\ce{Co49Ni21Ga30}$
(I suppose the numbers indicate the mass percentage).

To get the molar mass, is it correct to use the formula below?

Mol_mass_compound = Mol_mass_Co*0.49 + Mol_mass_Ni*0.21 + Mol_mass_Ga*0.30


Regarding the density, how do you suggest to proceed? Thanks!

• Welcome to Chemistry.SE. Your equation would be correct if a sum formula would be a table of weight percentages. But please note that one of the most important concepts in chemistry is the mole. The molecular weight is the sum of products of atom weights (of an element) and the number of atoms (of that element) in a molecular formula. – Klaus-Dieter Warzecha Apr 23 '15 at 3:08