What will be the residue left on the watch glass on heating blue ink in it?

Classify the following as physical or chemical properties:
Most metal oxides form alkalis on interacting with water.

What is a mixture? Give two example of mixtures.

How will you differentiate between a suspension and a colloid?

You are given two liquids, one a solution and the other a compound. How will you distinguish the solution from the compound?

Classify the following materials as homogeneous mixtures and heterogeneous mixtures: Soda-water, Wood, Air, Soil, Vinegar, Alcohol and water mixture, Petrol and water mixture, Chalk and water mixture, Sugar and water mixture, Copper sulphate solution.

The ‘sea water’ can be classified as a homogeneous mixture as well as a heterogeneous mixture? Comment.

On heating calcium carbonate gets converted into calcium oxide and carbon dioxide:
Is this a physical or a chemical change?

Give some examples of Tyndall effect observed in your surroundings?