NCEA Level 3 Chemistry (AS91393) Practice Exam 2025 – Complete Aqueous Chemistry Prep

The mole fraction of solute in a solution is defined as the number of moles of the solute divided by the total number of moles present in the solution. This measure provides a way to express the concentration of a solute in a solution relative to the overall composition of the solution, which includes both the solute and any solvent present.

To calculate the mole fraction, you first need to determine the number of moles of the solute. You would then find the total number of moles in the solution, which encompasses the moles of solute and the moles of solvent. By dividing the moles of solute by this total number, you obtain the mole fraction, a dimensionless quantity that reflects the ratio of the solute to the solution's overall composition.

This approach is particularly useful in various applications, including calculations involving the properties of mixtures and in situations where molar ratios are essential for understanding chemical reactions or solutions.