CBSE Class 9 Science Exploring Mixtures and Their Separation (Class 9 NCERT New) Quiz 4

1. Name two types of crystals you might observe in everyday life as mentioned in the worksheet.

A Salt and sugar crystals B Diamond and emerald crystals C Ice and quartz crystals D Gold and copper crystals

2. What do you observe? Did you get crystals? If yes, is this a good way to experiment? Explain.

A Crystals are observed, and this is a good way to experiment. B No crystals are observed, and this is not a good way to experiment. C Crystals are observed, but this is not a good way to experiment. D No crystals are observed, but this is a good way to experiment.

3. To test the hypothesis that cooling a hot, saturated solution of copper sulfate rapidly in ice-cold water produces smaller and less well-formed crystals than cooling it slowly at room temperature, which experimental design should be used?

A Prepare two identical hot, saturated solutions of copper sulfate; cool one rapidly in ice-cold water and the other slowly at room temperature, then compare the crystals formed. B Prepare a single solution and cool it only in ice-cold water, then observe the crystals. C Prepare two solutions and cool both rapidly in ice-cold water, then compare the crystals. D Prepare two solutions and cool both slowly at room temperature, then compare the crystals.

4. If equal masses of hot, saturated solutions of compounds ‘A’ and ‘B’ are cooled from 80°C to 60°C, which solution is likely to deposit more solid?

A Compound ‘A’ is likely to deposit more solid. B Compound ‘B’ is likely to deposit more solid. C Both solutions will deposit equal amounts of solid. D Neither solution will deposit any solid.

5. Will there be any change in the size of common salt crystals if the rate of evaporation is increased or decreased? Explain.

A Yes, the size of the crystals will change depending on the rate of evaporation. B No, the size of the crystals will remain the same regardless of the rate of evaporation. C The size of the crystals will only change if the temperature is altered. D The size of the crystals will decrease if evaporation is slowed down.

6. The process can be described as:

A A sequence of steps to achieve a specific outcome. B A random collection of unrelated actions. C A single action performed repeatedly. D An undefined set of events with no purpose.

7. Which method was used to obtain panga salt?

A Evaporation of sea water B Boiling concentrated sea brines C Freezing sea water D Mixing salt with sand

8. When we allow a solvent to evaporate to get a solute, such as salt from a salt solution, the solvent disappears. However, we may also want to recover the solvent. What should we do then? (Fill in the blank) To recover the solvent, we can use the process of _______.

A distillation B filtration C crystallization D sublimation

9. A homogeneous mixture of two miscible liquids can be separated by heating the mixture until the liquid with the lower boiling point vaporises. The vapour is then cooled, turning back into liquid. This process is known as:

A Filtration B Distillation C Evaporation D Chromatography

10. In the distillation process, what happens to the vapour after it is formed from heating the liquid?

A It is discarded B It is cooled and turns back into liquid C It is absorbed by another substance D It remains as vapour