what are atomic precentage of nickel and copper if alloy contains 70wt%NI and 30wt% CU?

Answer 1

Molar masses: Ni is 58.71 g/mol; Cu is 63.54 g/mol.
Therefore: 70/58.71=1.192 mol of Ni; 30/63.54=0.472 mol of Cu;
Total mols: 1.192+0.472 = 1.664:

mol % : (1.192/1.664) x100 = 71.6 % of Ni;
(0.472/1.664) x100 = 28.4 % of Cu.
Mol % is the same as atomic %