van 't Hoff factor

(noun)

A measure of the effect of a solute on colligative properties.

Related Terms

Examples of van 't Hoff factor in the following topics:

  • Freezing Point Depression

    • In this equation, $\Delta T_f$ is the freezing point depression, Kf is the freezing point depression constant, and i is the van 't Hoff factor.
    • The freezing point depression constant changes depending on the solvent, and the van 't Hoff factor accounts for the number of particles that a dissolving solute creates in solution.
    • In simplest terms, this means it has an "i" factor of 2.

  • Osmotic Pressure

    • Here, i is the van 't Hoff factor, M is the molarity of the solution, R is the gas constant, and T is the absolute temperature in Kelvin.

  • The Arrhenius Equation

    • H. van 't Hoff provided physical justification and interpretation for it.
    • In this equation, k is the rate constant, T is the absolute temperature, Ea is the activation energy, A is the pre-exponential factor, and R is the universal gas constant.
    • Take a moment to focus on the meaning of this equation, neglecting the A factor for the time being.
    • Let's look at the pre-exponential factor A in the Arrhenius equation.
    • Plot of ln(k) versus 1/T for the decomposition of nitrogen dioxide

  • Real Gases

    • It is almost always more accurate than the van der Waals equation and frequently more accurate than some equations with more than two parameters.
    • $RT = P(V_{m} - b) + a \cdot \frac{V_{m} - b}{V_{m} \cdot (V_{m} + b) \cdot T^{1/2}}$
    • Note that a and b here are defined differently than in the van der Waals equation.
    • However, these systems are used less frequently than are the van der Waals and Redlich-Kwong models.
    • Deviation from ideality can be quantified using the compressibility factor Z:

  • Commitment to Vietnam

    • The South Vietnamese governement was run by a twelve member military revolutionary council, headed by General Duong Van Minh.
    • The Gulf of Tonkin Incident proved an escalating factor of the war and justification of continued American presence in Vietnam.
    • In 1966, the junta selected General Nguyễn Văn Thiệu to run for president with Ky on the ballot as the vice-presidential candidate in the 1967 election.
    • Robert McNamarra recounts the confusion and uncertainty surrounding the Gulf of Tonkin Incident, ultimately reporting that "It didn't happen."