2026 GCE Science Paper 2 Quick Revision | Separation of Mixtures

[00:00:02]I in today's lesson.

[00:00:05]So, it is a risky to go in the exam without knowing uh such chemistry uh questions.

[00:00:15]Like the question was saying, "The experimental setup that the follows shows a mixture of sand and iodine crystals in an evaporating dish."

[00:00:29]So, this was uh uh the evaporating dish, this one.

[00:00:34]So, this is topic is under separation techniques. So, you should But, before you go and write your science paper two exam, make sure you pass through uh separation techniques question. Mostly, sometimes they can bring this one or sometimes they can bring other uh questions in the exam on section B. They like doing that. So, just go and study on separation funnel and other separation what techniques, filtration, fractional distillation. So, now, the question was saying, "Describe how the mixture of sand and iodine crystals can appropriately be separated." So, this iodine crystals uh mixed with sand can only be separated when it is heated.

[00:01:21]So, the moment it is heated, it will changes into what? Gas. That means you you're going to say it will subli- su- su- su- sublime. Because sublimation is a process by which a solid changes into what?

[00:01:36]A gas direct. So, that means this one is going to change into a gas, then the sand is going to remain in this evaporating dish. So, this is how you can write the answer. You can say, um Heat Heat the mixture.

[00:01:58]Mixture so that the the the iodine I don't I don't know I don't iodine sublimes.

[00:02:23]Then Andy you say Andy correct correctly on a cold what the surface.

[00:02:47]leaving the sandy behind.

[00:02:57]So the most important thing is that you heat the what?

[00:03:00]This mixture and the the uh the what?

[00:03:04]The you can see the iodine is going to change into gas then the the what? The sand is going to leave be left what? Behind. Then the other question you are saying explain why bottled mineral water is not pure water.

[00:03:18]Why is this water that you drink in in bottled mineral water is not pure water?

[00:03:24]So you can say you can say bottled mineral bottled mineral mineral water is not pure because it contains so some of you think it's it's pure. So, you say it contains dissolved what?

[00:04:00]dissolved the minerals and salts.

[00:04:09]That's the reason it's not pure water because it contains dissolved water minerals and salts.

[00:04:17]Um The last question was saying, "Give one uh criterion for purity of a substance." You can say a pure a pure substance You can say a pure substance has a a fixed melting what? Melting point.

[00:04:53]That's what you need to understand. Pure substances melt at one specific temperature. That's what you need to understand. So, uh don't forget to subscribe for more exam preparation with your volunteer, the teacher of grace, the Unza graduate teacher, where learning is made simple.