The figure shows two identical volumetric flasks containing the same solution at two temperatures. (b) Does the molality of the solution change with the change in temperature? [Section 13.4]

Verified step by step guidance

Understand the concept of molality: Molality (m) is defined as the number of moles of solute per kilogram of solvent. It is expressed as \( m = \frac{\text{moles of solute}}{\text{kilograms of solvent}} \).

Recognize that molality is independent of temperature: Unlike molarity, which depends on the volume of the solution and can change with temperature, molality is based on the mass of the solvent, which does not change with temperature.

Consider the effect of temperature on the solution: When temperature changes, the volume of the solution may expand or contract, but the mass of the solvent remains constant.

Conclude that since molality is based on the mass of the solvent and not the volume of the solution, it does not change with temperature.

Therefore, the molality of the solution remains constant despite changes in temperature.

Verified video answer for a similar problem:

This video solution was recommended by our tutors as helpful for the problem above.

Video duration:

Was this helpful?

Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

Molality

Molality is a measure of the concentration of a solute in a solution, defined as the number of moles of solute per kilogram of solvent. Unlike molarity, which is affected by changes in volume due to temperature, molality remains constant because it is based on the mass of the solvent, which does not change with temperature.

Effect of Temperature on Solutions

Temperature can influence the physical properties of a solution, such as density and viscosity, but it does not affect the molality. As temperature increases, the kinetic energy of the molecules increases, which may lead to changes in solubility, but the mass of the solvent remains unchanged, keeping the molality constant.

Identical Volumetric Flasks

Using identical volumetric flasks ensures that the volume of the solution remains constant regardless of temperature changes. This consistency is crucial for comparing the properties of the solutions at different temperatures, as it eliminates volume as a variable, allowing for a clear focus on how temperature affects other properties like molality.

Recommended video:

Guided course

02:42

Gas Identity Determination using Molar Mass Example

Related Practice

Textbook Question

The structures of vitamins E and B6 are shown below. Predict which is more water soluble and which is more fat soluble. [Section 13.3]

Textbook Question

This portion of a phase diagram shows the vapor–pressure curves of a volatile solvent and of a solution of that solvent containing a nonvolatile solute. (b) What are the normal boiling points of the solvent and the solution? [Section 13.5]

views

Textbook Question

Suppose you had a balloon made of some highly flexible semipermeable membrane. The balloon is filled completely with a 0.2 M solution of some solute and is submerged in a 0.1 M solution of the same solute:

Initially, the volume of solution in the balloon is 0.25 L. Assuming the volume outside the semipermeable membrane is large, as the illustration shows, what would you expect for the solution volume inside the balloon once the system has come to equilibrium through osmosis? [Section 13.5]

Textbook Question

The diagrams shown represent an emulsion, a true solution, and a liquid crystal. The colored balls represent different liquid molecules. Which diagram corresponds to which type of mixture? [Section 13.6]