Tag: crystallisation

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Questions Related to crystallisation

Multiple choice chemistry changes around us crystallisation process of separating components of a mixture physical changes

What is a chemical change?

  1. Change in size, shape

  2. Change from one substance to another new substance

  3. Change in temperature from lower to higher

  4. None of above
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

A chemical change is a process where one or more substances are converted into one or more new substances. Examples: Explosion of fireworks that produces heat, light, sound and unpleasant gases, breaking down of ozone in the ozone layer by the UV radiations.


Hence, the correct option is $B$

Multiple choice chemistry changes around us crystallisation process of separating components of a mixture physical changes

Which of the following is not a chemical change?

  1. Whipping eggs

  2. Burning wood

  3. Digestion

  4. All of above
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

In whipping of eggs, the air is introduced into the fluid but no new substance is formed. Hence, it is a physical change. Digestion and burning of wood results in the formation of new substances. Thus, it is a physical change.


Hence, the correct option is $\text{A}$

Multiple choice chemistry changes around us crystallisation process of separating components of a mixture physical changes
An example of chemical change is :

  1. water condensing on the outside of your cold beverage

  2. bending a wire

  3. slicing bread

  4. freezing water

  5. burning a candle
Reveal answer Fill a bubble to check yourself
E Correct answer
Explanation

Burning of candle is a chemical change because the wax gets converted into carbon dioxide whereas the rest of the options represent the physical change.


Hence the correct option is E.

Multiple choice chemistry changes around us crystallisation process of separating components of a mixture physical changes

Insoluble impurities from solution during crystallization are removed by :

  1. drying

  2. filtration

  3. heating

  4. cooling
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Heating is the process of increasing the temperature of a body from its original temperature.

Cooling is the process of decreasing the temperature of a body from its original temperature.
Filtration is the process of separating small particles of solid matter from a liquid, by causing the liquid to pass through the pores of some substance, called a filter.
Insoluble impurities from solution during crystallization are removed by filtration as the insoluble solid particles passed through the filter.
Drying is the process of drying up the liquid present on any material by heating the material.
Option B is correct.

Multiple choice chemistry changes around us crystallisation process of separating components of a mixture physical changes

While forming crystals, it is important to :

  1. evaporate to dryness to get purest possible crystals

  2. attach gas syringes to collect fumes

  3. not evaporate water of crystallization

  4. use high flames
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Crystals contain water of crystallization hence during formation of crystals water of crystallization should not be evaporated.

Also, crystallization is the process of formation of crystals. Crystals is defined as the highly organized molecule into a well-known structure.

Multiple choice chemistry changes around us crystallisation process of separating components of a mixture physical changes

Which of the following is not a feature of chemical change?


(I) Original substance can be obtained by simple physical methods.
(II) It is a temporary change.
(III) The new substances formed have properties different from those of the reacting substances.

  1. I, II

  2. I, III

  3. II, III

  4. All of the above
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

One more new substances one formed in a chemical change. The new substances formed have properties different from those of the reacting substances. A chemical change is always accompanied by the absorption or evolution of energy in the form of heat, light or sound.