Particle Model of Matter Exam Style Q's

Question 1

1 . 2 Explain what is meant by a physical change.

Answer 1

A physical change is one in which no new substances are formed [1].
Physical changes are easily reversible [1].

Question 2

2 . 2 As the temperature of a substance increases, what happens to its
internal energy? Tick one box.

Answer 2

It increases ✔⃞

Question 3

2 . 3 An ice cube is placed into a glass of water which is at room temperature.
After 15 minutes, the ice has melted completely.
Using the particle model, explain fully what happens to the ice as it melts.

Answer 3

• The particles in a solid are packed tightly, and vibrate about fixed
positions [1]
• When the ice cube (which is at a lower temperature) is placed into the
water (which is at a higher temperature), there is a net flow of heat
energy from the water to the ice [1]
• This increases the internal energy stored by/temperature of the ice
• As its temperature increases, the particles within the ice vibrate more
rapidly (about their fixed positions) [1]
• When these particles have enough energy, the bonds holding them
together will be broken, and they will be able to move freely/flow
around one another [1]