Describe the separation of mixtures and identify substances that settle or change colour.

Here are the answers to your questions:

1. Revision activity

• 1.a. List the substances that settled at the bottom.
  • In the curry powder mixture: Curry powder
  • In the chalk and water mixture: Chalk
• 1.b. Write the substances that did not change in all three mixtures.
  • Water (in the curry powder and chalk mixtures, and likely implied in a third mixture if it were present).
• 1.c. Name a substance that changed the colour of the other substance.
  • Curry powder changed the color of the water.

2. Draw and label the substances to show what happens when you mix the following:
(As an AI, I cannot draw, but I will describe what happens.)

• 2.a. Water and sand
  • When mixed, the sand will settle at the bottom of the container because it is denser and insoluble in water. The water will remain above the sand.
• 2.b. Water and oil
  • When mixed, the oil will form a distinct layer on top of the water because oil is less dense than water and immiscible (does not mix) with it.
• 2.c. Corn kernels and beans or samp and beans.
  • When mixed, the corn kernels (or samp) and beans will simply intermingle, forming a heterogeneous mixture where individual components are still visible and distinguishable.

3. How would you separate the mixtures in Question 2?

• 3.a. Water and sand
  • First, use decantation to carefully pour off the water after the sand has settled. Then, use filtration to separate any remaining fine sand particles from the water.
• 3.b. Water and oil
  • Use a separating funnel to allow the denser water to be drained off, leaving the oil layer behind. Alternatively, decantation can be used by carefully pouring off the oil layer.
• 3.c. Corn kernels and beans or samp and beans.
  • Use hand-picking to manually separate the larger corn kernels (or samp) from the beans. If there is a significant size difference, sieving could also be used.

4. We make a mixture of cinnamon and sugar to sprinkle over pancakes. Suggest a way of separating the sugar from the cinnamon. Explain your answer.

• Method:
  1. Add water to the mixture of cinnamon and sugar.
  2. Stir well to dissolve the sugar. The cinnamon will not dissolve and will remain suspended.
  3. Filter the mixture. The insoluble cinnamon will be collected on the filter paper (residue).
  4. The sugar solution (filtrate) will pass through the filter paper.
  5. Evaporate the water from the sugar solution to obtain solid sugar crystals.
• Explanation: This method works because sugar is soluble in water, while cinnamon is largely insoluble. This difference in solubility allows for the separation of the two components.