Question

What is the mass of sodium thiosulphate pentahydrate required to prepare 250cm3 of a 0.14mol/dm3 solution

Answer 1

Strength of the sodium thiosulphate solution to be produced is 0.150M= 0.150mol/L×248.2g/mol=37.23g/L. So 1L or 1000 mL solution ...

Missing: 0.14mol/dm3 ‎| Must include: 0.14mol/dm3

Answer 2

Mass = 8.68g

Step-by-step explanation:

Mass = Concentration × Molar mass × Volume (in dm^3)

but, concentration = 0.14 mol/dm^3.

volume = 250 cm^3 = 0.25 dm^3.

Molar mass of Na2S2O3 . 5H2O

= (2×23)+(2×32)+(3×16)+(5×18)

= 248 g/mol

hence, mass = 0.14 × 248 × 0.25

Mass = 8.68 g.

I HOPE IT'S OK?