N/Na = m/M;
N = Na*m/M; m = pV;
1) m1 = p1V1; V = 4/3пR^3;
m1 = (13500*4*3.14*(10^-3)^3)/3 = 0.00005652 = 5652*10^-8;
N = (6*10^23*5652*10^-8)/(200*10^-3) = 1.7*10^20;
2) m2 = (10^3*4*3.14*(10^-3)^3)/3 =0.000004186 = 4187*10^9;
N = (6*10^23*4187*10^9)/(18*10^-3) = 1.4*10^38;