Chemical Potential and Gibbs Energy That Depends on Composition · seed 1 · A4, ink-friendly. The answer key prints on its own page for grown-ups.

The push that moves matter around

Science · Chemistry · ages 20-21
Name ______________________   Date ____________

  1. Matter flows from high chemical potential to low chemical potential.

    Circle one:   True   False

  2. What is the chemical potential of a component?

    • The heat released when it burns
    • The speed at which it flows
    • Gibbs change on adding a little

  3. The chemical potential of water matches in ice and liquid water. What does that mean?

    • The ice melts instantly
    • Phases coexist in equilibrium
    • Heat must be flowing between them

  4. In an ideal mixture, how does one component potential change as its fraction falls?

    • It stays fixed, since ideals never shift
    • It slides down with log fraction
    • It climbs in direct proportion

  5. Two miscible liquids mix on their own with no heat released. Why?

    • Their chemical potentials were already equal before mixing
    • The entropy of mixing drags their potentials down
    • Mixing always releases hidden heat

  6. Where does the equilibrium constant come from in this picture?

    • Product and reactant potentials match
    • From dividing enthalpies by entropies
    • From measuring how fast equilibrium arrives

  7. A student says a positive standard Gibbs energy means the reaction can never run forward. What is wrong?

    • One mix only; a new mix can flip sign
    • Positive values always reverse themselves with time
    • Gibbs energy has no link to direction at all

  8. A solute has mu of 5 units in tank A and 2 units in tank B. The tanks are joined. What happens?

    • Solute flows from A to B
    • Solute flows from B to A
    • Nothing moves, since both tanks hold solute
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Answer key

For grown-ups. Fold this page away before handing over the rest.

The push that moves matter around W1-mt_Tdl6K-gFO3-s1

  1. True · The downhill slide in mu is what drives the flow.
  2. Gibbs change on adding a little · It is the partial molar Gibbs energy of that component.
  3. Phases coexist in equilibrium · Matched potentials mean equilibrium between the phases.
  4. It slides down with log fraction · Dilution lowers mu through the log term.
  5. The entropy of mixing drags their potentials down · Each component gains room, and that entropy fall in G drives mixing.
  6. Product and reactant potentials match · Equality of potentials at equilibrium rearranges into the constant.
  7. One mix only; a new mix can flip sign · Composition shifts every potential, so the verdict can change with the mix.
  8. Solute flows from A to B · Flow runs from the higher potential toward the lower one.
Worksheet · LightMySky