Diffusion and dilution (practical)

Describe and explain the bromine gas practical. What would happen after 5 minutes and why?

Brown bromine gas particles would diffuse into the jar with air as the net movement of particles move from a high concentration region to a low concentration region.

This means that after 5 minutes there would be a uniformly lighter brown colour in both jars...

...since air and bromine particles move randomly and there are gaps between the particles so they mix together.

What is safety precautions must you follow when performing diffusion experiment with bromine? Why?

Must be prepared in a working fume cupboard, wearing a protection and chemical resistant gloves

Bromine is toxic

Describe and explain the diffusion practical in liquids where small crystals of purple potassium manganate are added into a gas jar of water. Movement of particles, what happens after 4 hours? Why?

When potassium manganate (VII) crystals are dissolved in water, a purple solution is formed.

Potassium manganate molecules diffuse through the solution, from a region of high concentration to a region of low concentration. After 4 hours the concentration of particles is now evenly spread and there is a uniform lighter purple colour.

The water and potassium manganate (VII) particles are moving randomly and the particles can slide over each other. The particles can therefore easily mix together

Would diffusion happen quicker in gases or in liquids? Why? Which place would occur the fastest, not including gases?

Diffusion in liquids is slower than in gases because the particles in a gas have more kinetic energy and move quicker than liquid particles.

Also particles in a liquid are closer together than in a gas so there is less space for particles to move without colliding with one another.

In a vacuum because there are no particles to collide into.

Describe and explain the dilution practical of potassium manganate in water. Why does this happen?

Description:

When potassium manganate (VII) crystals are dissolved in water, the solution can be diluted several times.

The colour fades but does not disappear until a lot of dilutions have been done.

Explanation:

This indicates that there are a lot of particles in a small amount of potassium manganate (VII) and therefore the particles must be very small

Why does the white ring of ammonium chloride appear nearer to the hydrochloric acid?

Ammonia will travel faster and further in the same amount of time as hydrochloric acid as its particles are smaller and have a smaller molecular mass than HCL particles (lighter).