Question

What volume in liters of 4.50×10−2 M KH2AsO4 contains 2.70 g KH2AsO4?

Answer 1

Ans :- Volume of KH₂AsO₄ = 0.333 L

Explanation :-

Given mass of KH₂AsO₄ = 2.70 g

As,

Gram molar mass of KH₂AsO₄ = 180.03 g/mol

From the definition of number of moles,

Number of moles = Given mass in g / Gram molar of substance

So,

Number of moles of KH₂AsO₄ = Given mass of KH₂AsO₄ in g / Gram molar mass of KH₂AsO₄

= 2.70 g / 180.03 g/mol

= 0.015 mol

Also from the definition of Molarity,

Molarity = Number of moles of substance / Volume of solution in L

So,

Volume of KH₂AsO₄ = Number of moles of KH₂AsO₄ / Molarity of KH₂AsO₄

= 0.015 mol / 4.50 x 10^-2 M

= 0.333 L

Hence, Volume of KH₂AsO₄ = 0.333 L