Question

Define mass percent and mole fraction. Why molality is better unit to express concentration than molarity Explain.​

Answer 1

Answer:

Mass percentage is one way of representing the concentration of an element in a compound or a component in a mixture. Mass percentage is calculated as the mass of a component divided by the total mass of the mixture, multiplied by 100%.

mass percent = mass/total mass * 100

Explanation:

In chemistry, the mole fraction or molar fraction is defined as unit of the amount of a constituent, nᵢ divided by the total amount of all constituents in a mixture.

Xa=na/na+nb

Xb=nb/na+nb

Molality is a better unit to express concentration b/c molality does not depend on the temperature of the solution whereas molarity changes with temp.(b/c volume changes with the temperature).