1. M = ?
n = 1 mol
m = 12g
n = m/M => M = m/n = 12/1 = 12g/mol
2. m = ? (g) N2
V = 30mL = 0,03L
n = V/Vm = m/M => m = M×V/Vm = 28×0,03/22,4 = 0,0375g N2 = 37,5mg N2
3. m CuO = ?
n = 3 moli CuO
MCuO = ACu + AO = 64+16 = 80g/mol
n = m/M => m = n×M = 3×80 = 240g CuO
4. m NaI = ?
n = 0,6 moli NaI
MNaI= 150g/mol
n = m/M =>m = n ×M = 0,6×150 = 90g
5.M = ?
n = 1 mol
m = 24g
n= m/M => M = m/n = 24/1 = 24g/mol