Chemical Change

Q. Give an example which shows both physical and chemical changes

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5) Photosynthesis is a _________ change

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Rusting of iron is an example of a chemical change.

1. True

2. False

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4. A change occurs during the growth of plants. What type of change it is?

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Question 7

Neutralisation reaction is a
(a) physical and reversible change.
(b) physical change that cannot be reversed.
(c) chemical and reversible change.
(d) chemical change that cannot be reversed.

Q. Which of the following is not a method to prevent rusting?

1. Galvanisation
2. Painting
3. Polishing
4. Applying grease

Q.

The process of depositing a thin layer of zinc metal on iron objects is called

Q. Is growth a physical change or a chemical change ?

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What is the name given to the liquids which dissolve solids?

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When a candle burns, both physical and chemical changes take place. Identify these changes. Give another example of a familiar process in which both the chemical and physical changes take place.

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What is the type of the change, when paper is burnt to produce ash?

1. Temporary and physical change

2. Permanent and physical change

3. Temporary and chemical change

4. Permanent and chemical change

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27. Name the following:

a. a solid that dissolves in water

Q. Is aging of human beings is chemical or physical change

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Identify solutes and solvents in the solution of alcohol in water. Mention the physical state of solute and solvents.

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Explain why burning wood and cutting it into small pieces are considered two different types of changes.

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• Classify the following change in as many ways as possible.
  Growth of a tree

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Mention any three changes that take place in our body. [3 MARKS]

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The process of applying a protective coating of zinc on iron or steel to prevent them from rusting is called ___.

Q. Copper sulphate is a blue coloured solution which undergoes a chemical change when iron nails are dropped inside it. Which amongst the given indicators will help to identify the chemical change taking place?

1. Evolution of gas
2. Production of sound
3. Evolution of heat
4. Change in colour

Q. There are three test tubes containing an iron nail, each at different conditions as shown below:

Calcium chloride is used in test tube (iii) to remove all the water present inside the test tube. In which of the above three test tubes will rusting not take place?

1. Test tube (i) only
2. Test tube (iii) only
3. Both test tube (i) and (ii)
4. Both test tube (ii) and (iii)

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The substance present in larger component in the solution is known as_______

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Classify the following changes into physical change and chemical change:

Melting of ice.

Q. Categorise these changes as reversible or irreversible.
a. Melting of an ice candy
b. Cooking of food
c. Souring of milk

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During a chemical change there is a change in the mass of original substance:

1. True

2. False

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Give one example of each of the transformations of electrical energy into heat, light and mechanical energy and one example of the transformation of kinetic energy into electrical energy.

Q. 1) Explain physical and chemical changes are useful in day to day life

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Some changes are given below.

(a) Freezing of water

(b) Melting of ice

(c) Boiling of water

Are these considered as physical changes? If yes, give the reason.

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3. Which of the following is a chemical change?

1. the making of idlis

2. grinding rice

3. powdering of sugar crystals

4. breaking of a window pane

Q. A chocolate bar is broken into smaller pieces. Which type of change is this?

1. Slow
2. Chemical
3. Physical
4. slow and physical

Q. Which amongst the following substances can undergo both physical and chemical change simultaneously while burning?

1. Petrol
2. Candle
3. Paper
4. Wood