# Three States of Matter – Structured Question 3

Structure Question 3:
The table below shows the melting and boiling points of three different substances.

 Substance Melting Point Boiling Point H -120°C -5°C I 45°C 98°C J 10°C 350°C

Answer:

1. What is the physical state of H, I and J at room temperature (25°C)?
H: gaseous I: solid J: liquid
2. Which substance diffuses the fastest at room temperature? Explain your answer.
Substance H. Because substance H exist as a gas at room temperature, hence there is a lot of empty space between the particles. Other than that, the particles of H have the highest kinetic energy.
3. Draw some diagrams to show the arrangement of particles of substance I at 40°C, 80°C and 120°C.At 40°C

At 80°C

At 120°C

4. What is the name of the process which atoms or molecules of a substance in liquid state gain sufficient energy to enter the gaseous state below boiling point?
Evaporation
5. Define boiling point.
Boiling Point is the temperature at which the pressure exerted by the surroundings upon a liquid is equalled by the pressure exerted by the vapour of the liquid.
6. Sketch the graph of temperature against time for substance I when it is cooled from 120°C to room temperature.