Question

Berapa gram zat terlarut yg terdpt dlm 1 mL CaCl2 0,5 M, 100mL Ca(OH)2 0,4 M dan 10 mL KNO3 0,2 M?

Answer 1

1 mL CaCl₂ 0,5 M → 0,5 mmol CaCl₂
massa = mol × Mr
   = (0,5)(111)
   = 55,5 mg


100mL Ca(OH)₂ 0,4 M → 40 mmol Ca(OH)₂
massa = mol × Mr
   = (40)(74)
   = 2960 mg
   = 2,96 g


10 mL KNO₃ 0,2 M → 5 mmol KNO₃
massa = mol × Mr
   = (5)(101)
   = 505 mg


SOLVED!

Answer 2

CaCl2 ==> V = 1 mL, M = 0,5 M
n = M.V = 0,5 M . 1mL = 0,5 mmol = 5 × 10^-4 mol
Mr CaCl2 = 111
m = Mr . n = 111 . 5 . 10^-4 = 5,55 . 10^-2 gram = 0,0555 gram

Ca(OH)2 ==> V = 100 mL, M = 0,4 M
n = M . V = 0,4 M . 100 mL = 40 mmol = 4 × 10^-2 mol
Mr Ca(OH)2 = 74
m = Mr . n = 74 . 4 . 10^-2 = 2,96 gram

KNO3 ==> V = 10 mL , M = 0,2 M
n = M . V = 0,2 M . 10 mL = 2 mmol = 2 × 10^-3 mol
Mr KNO3 = 101
m = Mr . n = 101 . 2 . 10^-3 = 2,02 × 10^-1 gram = 0,202 gram