Sound — Science STD 9 — Question

Draw a labelled diagram of the fractional distillation apparatus used for separating a mixture of alcohol and water.

With the help of a labelled diagram, describe the method of separating ammonium chloride from a mixture of ammonium chloride and common salt. Mention the difference in the properties of ammonium chloride and sodium chloride which has made this separations possible.

Give the main differences between physical changes and chemical changes.

What do you understand by the terms “balanced forces” and “unbalanced forces”? Explain with examples.

If the back of your hand is moistened with alcohol, you will find that it rapidly becomes dry. Why is it that while it is drying, your hand feels cool?

How will you separate a mixture of iron filings, chalk powder an common salt?

How would you prepare a saturated solution of sodium chloride in water at 25°C? What will happen if this solution is cooled to 10°C?

Universal law of gravitation states that every object exerts a gravitational force of attraction on every other object. If this is true, why don’t we notice such forces? Why don’t the two objects in a room move towards each other due to this force?

Discuss the method of separating a mixture containing chalk powder, iron fillings and naphthalene.