Name: States of Matter
Uploaded: 2019-07-19
Duration: 7 min 38 s
Description: The Earth is composed of matter which is found in three different states. Watch this video to learn about these three states and their similarities and differences.

Question

Bromine is a reddish-brown liquid. Some liquid bromine is placed in a closed jar. The bromine starts to evaporate. The colour of the vapour above the liquid bromine becomes darker and darker. After a time the bromine vapour does not get any darker. Use ideas about moving particles to explain these observations.

Accepted Answer

At first, bromine molecules escape from the surface of the liquid to become vapour. As more and more molecules escape, the molecules in the vapour become closer together, and hence, the colour of the vapour above the liquid bromine becomes darker and darker. Eventually, the molecules with lower kinetic energy will not be able to overcome the attractive forces of neighbouring molecules. The vapour begins to condense. So some bromine molecules return to the liquid. Eventually, bromine molecules return to the liquid at the same rate as bromine molecules escape to the vapour. A position of equilibrium is reached. At equilibrium, the concentration of bromine molecules in the vapour remains constant. Thus, at equilibrium the bromine vapour in the closed jar, does not get any darker.

Lawrie Ryan and Roger Norris Solutions for Chapter: States of Matter, Exercise 10: Question

Lawrie Ryan Chemistry Solutions for Exercise - Lawrie Ryan and Roger Norris Solutions for Chapter: States of Matter, Exercise 10: Question

Questions from Lawrie Ryan and Roger Norris Solutions for Chapter: States of Matter, Exercise 10: Question with Hints & Solutions

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