Question

24mg memiliki kelimpahan 78,99% dan massanya adalah sebesar 23,9850 sma. 25mg memiliki kelimpahan 10,00% dan massanya adalah sebesar 24,9858 sma.26Mg memiliki kelimpahan 11,01% dan massanya 25,9826 sma. berapakah Ar Mg?

Answer 1

Massa rata" = (%kelimpahan isotop 1 x massa isotop 1) + (%kelimpahan isotop 2 x massa isotop 2) + (%kelimpahan isotop 3 x massa isotop 3)

massa rata" = (78,99% x 23,9850) + (10,00% x 24,9858) + (11,01 x 25,9826)
= (78,99/100 x 23,9850) + (10,00/100 x 24,9858) + (11,01/100 x 25,9826)
= (1894,57/100) + (249,858/100) + (286,068/100)
= 2430,496/100
massa rata" = 24,31 sma (dibulatkan)

Ar Mg = massa rata" 1 atom Mg / 1 sma
Ar Mg = 24,31 / 1 = 24,31

semoga membantu :)