6.1) The picture shows a balloon containing air.

a: Explain how the particles of air inside the balloon create pressure.
b: The air in the balloon is heated up by leaving it in a warm place.
Give two effects that this has on the air particles.
c: Describe one way in which the balloon changes when it is left in a warm place.

6.2) Hydrochloric acid produces a gas. So does ammonia solution. These two gases react when they meet to form a white solid called ammonium chloride.
Some cotton wool soaked in hydrochloric acid was placed at one end of a glass tube.
Some cotton wool soaked in ammonia solution was placed at the other end.
The diagram shows what happened.

a: What is the name of the process by which the gases move along the tube?
b: Explain how this process takes place.
c: The particles of hydrochloric acid have a greater mass than the particles of ammonia. Suggest why the ammonium chloride is formed nearer to the hydrochloric acid end of the tube than the ammonia solution end.

6.3) Sunita carries out an experiment to investigate diffusion. She uses water and a food dye to find out how the volume of water used affects the time the dye takes to spread evenly through the water.
Her prediction is that the more water she uses, the longer the time needed for the dye to spread through it.
a: Which variable will she change?
b: Which variable should she measure?
c: State two variables that she will need to keep the same.
d: How will she ensure her results are reliable? 
e: Draw a suitable results table for Sunita.
f: Sketch a graph to show what the results will look like if Sunita's prediction is true. Label the axes.