Lesson 3.1.5.2

3.1.5.2 Maxwell–Boltzmann distribution Quiz: AQA Chemistry, Unit 1

20 questions

Written by Revision Ninja · Last reviewed 11 October 2026

In partnership with Revision Ninja

Lesson 3.1.5.2, Maxwell–Boltzmann distribution: 20 multiple choice questions for the AQA Chemistry (7405), Unit 1: Physical chemistry, written with Revision Ninja.

Host it live on the board and students join with a game code on their own devices, or revise alone with Free Play. The answers are revealed in the game.

Host this setFree Play

The 20 questions

  1. What does a Maxwell-Boltzmann distribution show?

    • The bond enthalpies of molecules in the gas, averaged over all the bonds present
    • The spread of molecular energies in a gas at a given temperature
    • The pressure of a gas in a flask, measured at a fixed temperature and volume
    • The atomic masses of the elements present in the gas sample at the given temperature

  2. On a Maxwell-Boltzmann curve, what is plotted on the x-axis?

    • Volume of the container
    • Pressure
    • Molecular energy
    • Mass of the gas

  3. On a Maxwell-Boltzmann curve, what is plotted on the y-axis?

    • The activation energy of the reaction in kJ per mole
    • The number or fraction of molecules with that energy
    • The temperature of the gas on the kelvin scale
    • The mass of the molecules in the gas sample

  4. How does the peak of a Maxwell-Boltzmann curve change when the temperature rises?

    • It moves to the left and becomes taller and narrower
    • It stays in the same place, with only its height changing
    • It moves to the right and becomes lower and broader
    • It disappears completely as the gas heats up in the flask

  5. Which region of a Maxwell-Boltzmann curve shows molecules with energy at or above the activation energy?

    • The start of the curve at zero energy, where the molecules are at rest
    • The area to the left of zero energy, which is always empty on the curve
    • The height of the peak only, which shows the most common energy in the sample
    • The area to the right of the activation energy line

  6. What does the total area under a Maxwell-Boltzmann curve represent?

    • The pressure of the gas
    • The total mass of the molecules
    • The total activation energy
    • The total number of molecules

  7. Which statement about a Maxwell-Boltzmann curve at a fixed temperature is true?

    • It is symmetric about the origin
    • It has no peak
    • It starts at the origin and levels off at high energy
    • It starts at a non-zero value at zero energy

  8. At 400 K compared with 300 K, which statement about the average molecular energy is correct?

    • The average energy is higher at 300 K
    • The energies are equal at both temperatures
    • Temperature has no effect on molecular energy
    • The average energy of molecules is higher at 400 K

  9. At a higher temperature, how does the fraction of molecules above the activation energy change?

    • It is zero
    • It is smaller than at the lower temperature
    • It is equal to the lower temperature
    • It is greater than at the lower temperature

  10. Which change to temperature increases the number of molecules with energy above the activation energy?

    • Lowering the temperature
    • Raising the temperature
    • Reducing the volume only
    • Removing some of the gas

  11. At a higher temperature, which description of the curve is correct?

    • The curve has the same shape
    • The curve shrinks to zero
    • The peak is higher and shifted to lower energy
    • The peak is lower and shifted to higher energy

  12. What does a shift of the Maxwell-Boltzmann curve to the right mean?

    • The number of molecules has increased
    • The average molecular energy has decreased
    • The average molecular energy has increased
    • The pressure of the gas has fallen to zero

  13. Which statement about molecular energies in a gas is correct?

    • Only the fastest molecules have any energy
    • The energy distribution does not depend on temperature
    • Molecules have a range of energies, not all the same
    • All molecules have exactly the same energy

  14. What is true of the areas under Maxwell-Boltzmann curves at two different temperatures for the same sample?

    • They are greater at the higher temperature, because more molecules gain energy
    • They are equal, because the total number of molecules is the same
    • They are zero for both temperatures, because the area only shows the energy barrier
    • They are smaller at the higher temperature, because molecules spread across more energies

  15. Why does the Maxwell-Boltzmann curve have a long tail at high energies?

    • All molecules move at identical speeds, so the tail is produced by measurement error alone
    • The gas is ionised at high energies, so the tail shows where charged particles form
    • The temperature is zero at the far end of the tail, so the molecules have no motion
    • A few molecules have much higher energies because of random collisions

  16. Why is the peak of the curve lower and broader at a higher temperature, even though the total area is the same?

    • More molecules are produced at a higher temperature, so the whole curve grows larger in area
    • Molecules lose mass at high temperature, so the distribution spreads out across the chart
    • Molecules are spread over a wider range of energies, so the same number is spread out
    • The gas volume decreases at high temperature, so the molecules are squeezed into a narrower band

  17. Why does a small temperature rise often produce a large change in the number of molecules above the activation energy?

    • The number of molecules doubles for each degree of temperature rise in the closed flask
    • The average energy rises by a large factor, so every molecule gains enough energy to react
    • The high-energy tail is sensitive to temperature, so a small rise moves many molecules above the activation energy
    • Activation energy depends linearly on temperature, so it rises with every degree of heating

  18. What happens to a gas's distribution curve if its temperature is halved?

    • The peak moves to higher energy, so the molecules gain more energy as the gas cools
    • The curve disappears completely, because the molecules stop moving at half temperature
    • The peak moves to lower energy and the curve becomes taller and narrower
    • The curve becomes broader and flatter, so the molecules spread out across more energies

  19. A reaction's activation energy is lowered at the same temperature. What happens to the area under the curve to the right of the activation energy line?

    • It becomes zero
    • It decreases, so fewer molecules react
    • It increases, so more molecules have energy above the activation energy
    • It stays the same because the total number of molecules is constant

  20. Two gas samples at the same temperature have different molar masses. Which statement is correct?

    • Heavier molecules always have higher kinetic energy, so they reach the activation energy first
    • Molar mass changes the activation energy, so the heavier gas always needs more energy to react
    • Lighter molecules never have a distribution curve, because they are too fast to measure
    • Heavier molecules move more slowly, but at the same temperature they have the same average kinetic energy

All AQA Chemistry quizzes