chemical changes- grade 8

Burning of Magnesium ribbon is an example of

• Physical change

• Temporary change

• Chemical change

• None of the above

During a physical change, a substance undergoes a change in its

• Physical properties

• Chemical properties

• Both (a) and (b)

• None of these

Which among the following is a chemical change?

• Tearing of paper

• Cutting of wood

• Bursting of fire crackers

• Dissolving salt in water

Chemical reactions which liberate or absorb heat energy are known as

• Thermochemical reactions

• Photochemical reactions

• Electrochemical reactions

• None of the above

The process in which a substance undergoes decomposition by a absorption of electrical energy is known as

• Electrodes

• Electrolytes

• Electricity

• Electrolysis

Electroplating is a

• Thermochemical reaction

• Photochemical reaction

• Electrochemical reaction

• Exothermic reaction

Silver bromide turns black in sunlight. This is an example of

• Endothermic reaction

• Photochemical reaction

• Thermochemical reaction

• Electrochemical reaction

Two carbon rods connected to a battery is dipped in copper sulphate solution. What will you observe?

• Colour of carbon rod diminished

• There is a coating on carbon rod

• Colour of copper sulphate solution increases

• Nothing happens

Which of the following is not a part of electrochemical cells

• Zinc rod

• Copper rod

• Sulphuric acid

• Copper sulphate

Dry cell is used in

• Radio

• Watches

• Mobile phone

• Laptops