Question

Calculate the molarity of each of the following solutions `:`
`a. 30g` of `Co(NO_(3))_(2).6H_(2)O` in `4.3L` of solution
`b. 30mL` of `0.5 M H_(2)SO_(4)` diluted to `500mL`.

Answer 1

(a). Malar mass of `CO(NO_(3))_(2).6H_(2)O=310.7" g "mol^(-1)`
no. of moles `=30//310.7=0.0966`
vol. of solution `=4.3L`
Molarity `=0.0966//4.3=0.022M`
(b). 1000 mL of 0.5 M `H_(2)SO_(4)` contain `H_(2)SO_(4)=0.5` mole
30 mL of `0.5" M "H_(2)SO_(4)`
`=0.5//1000xx30=0.015` mole
volume of solution `=500mL=0.5L`
Molarity `=0.015//0.5=0.03M`