Exam code: 5070
A student noted the following observation in her laboratory notebook:
“Over several hours the particles spread from an area of high concentration to an area of low concentration. The mixture was never stirred.”
Which process is being described?
Diffusion of a substance in a liquid.
The particles of a solid during melting.
A liquid being frozen.
Diffusion of a substance through air.
Was this exam question helpful?
A small amount of bleach was accidentally spilled on a kitchen floor. After a while it was observed that the floor appeared to be dry and the whole kitchen smelled of bleach.
Which processes have occurred?
Evaporation and diffusion
Distillation and diffusion
Evaporation only
Diffusion only
Was this exam question helpful?
A student accidentally left a bottle of ammonia open in the corner of a laboratory. After a few minutes the entire laboratory smelled of ammonia.
Which process has occurred?
Dispersion
Diffusion
Evaporation
Distillation
Was this exam question helpful?
The table shows the relative molecular masses of four gases.
Gas | Relative molecular mass |
|---|---|
hydrogen, H2 | 2 |
nitrogen, N2 | 28 |
sulfur dioxide, SO2 | 64 |
chlorine, Cl2 | 71 |
All four gases are at the same temperature.
Which gas diffuses most quickly?
hydrogen
nitrogen
sulfur dioxide
chlorine
Was this exam question helpful?
Diffusion is very much slower in a solid than in a liquid or a gas.
Which statement explains why?
The particles in a solid have no energy.
The particles in a solid are all the same size.
The particles in a solid can only vibrate about fixed positions.
The particles in a solid are held together by weak forces.
Was this exam question helpful?
The diagram shows what happens when a blue soluble crystal is placed in a beaker of water.
Which row correctly describes the processes taking place?
| Chemical process | Dissolving | Diffusion |
A | |||
B | |||
C | |||
D |
Was this exam question helpful?
Which substance would diffuse most quickly?
carbon dioxide at 0 °C
carbon dioxide at 25 °C
neon at 0 °C
neon at 25 °C
Was this exam question helpful?
Three statements about diffusion are shown.
1 Diffusion happens because particles are moving randomly.
2 Diffusion is faster in a gas than in a liquid at the same temperature.
3 A gas with a higher relative molecular mass diffuses more quickly.
Which statements are correct?
1, 2 and 3
1 and 2 only
1 and 3 only
2 and 3 only
Was this exam question helpful?
A gas with a strong smell leaks at one end of a long corridor.
The smell is noticed at the far end of the corridor after 30 seconds.
Which change would make the smell reach the far end in a shorter time?
using a gas with a higher relative molecular mass
lowering the temperature of the corridor
using a gas with a lower relative molecular mass
using a longer corridor
Was this exam question helpful?
A few drops of a strongly smelling liquid are spilled on a bench. The smell is noticed across the room within one minute.
A few drops of the same liquid are added to a beaker of water. Its colour takes about an hour to spread through the water.
Both the room and the water are at the same temperature.
Which explains why the substance spreads so much more quickly through the air?
The liquid reacts with the water.
The liquid dissolves in water rather than diffusing through it.
The particles in air are much further apart than the particles in water.
Air has a lower relative molecular mass than water.
Was this exam question helpful?
The rate of diffusion of two gases, methane, CH4, and propene, C3H6, is measured using the apparatus shown.
Which gas diffuses at a faster rate and why?
| Fastest gas | Reason |
A | Propene | Propene molecules are heavier and so move faster. |
B | Methane | Methane is a lighter molecule. |
C | Propene | Propene is unsaturated so is more reactive. |
D | Methane | Methane molecules are smaller so fit through the hole more easily. |
Was this exam question helpful?
Hydrogen chloride and ammonia are gases which are given off by cotton wool soaked in concentrated solutions and placed at either end of a glass tube as shown.
When the gases react together they produce ammonium chloride, a white solid.
Which line on the diagram correctly shows where the ammonium chloride is formed?
Was this exam question helpful?
The rate of diffusion of four gases, neon (Ne), hydrogen chloride (HCl), ammonia (NH3) and oxygen (O2), is measured in a sealed container.
What is the order of the rate of diffusion of the gases from slowest to fastest?
HCl → O2 → Ne → NH3
O2 → HCl → NH3 → Ne
NH3 → Ne → O2 → HCl
Ne → NH3 → HCl → O2
Was this exam question helpful?
Fluorine, F2, and chlorine, Cl2, are released into identical tubes at the same temperature.
Fluorine diffuses faster than chlorine.
Which statement gives the correct reason, in terms of the particles that diffuse?
A fluorine atom has a smaller relative atomic mass than a chlorine atom.
A fluorine molecule has a smaller relative molecular mass than a chlorine molecule.
Fluorine is more reactive than chlorine.
A fluorine molecule contains fewer electrons than a chlorine molecule.
Was this exam question helpful?
A small amount of a coloured gas is released at one end of a long sealed tube containing air.
The tube is left undisturbed for several hours, until the colour is the same everywhere along it.
Which statement about the particles of the coloured gas is then correct?
They have all collected at the far end of the tube.
They are evenly spread and have stopped moving.
They are evenly spread but are still moving.
They have all reacted with the oxygen in the air.
Was this exam question helpful?