WAEC - Chemistry (2003 - No. 32)
What volume of 0.20 mol dm -3 NaOH solution would yield 5.0 g of NaOH on evaporation to dryness? [NaOH = 40g mol-1]
400 cm3
625 cm3
1000 cm3
1600 cm 3
คำอธิบาย
Conc. g/dm3 = 0.20 x 40 gmol -1 = 8 g/dm3
1000 cm3 of 0.20m NaOH contains 8g of NaOH :. 5g of NaOH will be contained in 5/8 x 1000 x 625cm3
1000 cm3 of 0.20m NaOH contains 8g of NaOH :. 5g of NaOH will be contained in 5/8 x 1000 x 625cm3