Pupil sheet · The particle model
The particle model — return questions
Name ______________________ Date ____________
Use one to two weeks after the lessons. Keep the notes and the lesson closed.
1. state / describe / explain
Answer from memory. (a) State one property that a liquid and a gas both have, and one property that a liquid has but a gas does not. (b) A bar of chocolate left in a hot car turns soft and runny. State the name of this change of state, and describe what happens to the arrangement and the motion of its particles. (c) Supplement. A metal key and the neon gas in a glowing sign tube are both at room temperature. The key keeps its shape, but the neon spreads out to fill its tube. State the particles that each is made of, and explain the difference in terms of the forces and distances between the particles.
(a) Shared, and liquid only
(b) Chocolate in a hot car
(c) The key and the neon
2. describe / explain / state / determine
Answer from memory. (a) Describe what specks of smoke in a closed cell look like through a microscope. (b) Explain, in terms of collisions, why the specks move like this. (c) Supplement. State what the specks are, and what hits them, using the correct scientific words. (d) State why this motion is evidence for the kinetic particle model of matter. (e) Describe how the motion of the particles of a gas changes as the gas is cooled, and what happens to their average kinetic energy. (f) In the model, the average kinetic energy of an air molecule is 3.11 × 10−21 J at −123 °C and 7.25 × 10−21 J at 77 °C. Determine the temperature at which the average kinetic energy reaches zero, and state its name.
(a) What the specks look like
(b) Why they move
(c) The right words
(d) Why it is evidence
(e) Cooling a gas
(f) Where the energy reaches zero