Question

Calculate the concentration of solutions containing:
a. 0.2 mole of sodium hydroxide dissolved in water and made up to 100cm³
b. 9.8 g of sulfuric acid dissolved in water and made up to 500cm³

Answer 1

Volume of acid = 100 ÷ 1000 = 0.1 dm3

Concentration of acid = 0.02 mol ÷ 0.1 dm3

= 0.2 mol/dm3

Answer 2

Answer:

a.NaOH          n=0.2mol       V=100cm=0.1dm3        C=?

C=n/V             n=0.2mol       V=0.1dm3

C=0.2mol/1dm3

C=2mol/dm3

b.H2SO4       m=9.8g           V=500cm3=0.5dm3     C=?

n=m/M           m=9.8g           M=98g*mol

n=9.8g/98g*mol            

n=0.1mol

C=n/V            n=0.1mol         V=0.5dm3

C=0.1mol/0.5dm3

C=0.2mol/dm3