Class 7 Physical and Chemical Changes

Which of the following is a physical change?

• Rusting of iron

• Melting of wax

• Combustion of magnesium ribbon

• Burning of candle

Tags

NGSS.MS-PS1-4

Which of the following is a chemical change?

• Cooking of vegetables

• Crumpling of paper

• Cutting of fruits

• Boiling of water

Tags

NGSS.MS-LS1-7

NGSS.MS-PS1-2

A chemical change may involve

• Change in color only

• Change in temperature only

• Evolution of gas only

• Any or all of the above

Tags

NGSS.MS-PS1-2

Conversion of milk to curd involves (choose all that applies)

• Change in color

• Change in taste

• Milk changes from liquid to semi-solid

• Irreversible change

Tags

NGSS.MS-LS1-7

NGSS.MS-PS1-2

Which of the following processes is used to prevent articles from rusting?

• Crystallization

• Galvanization

• Evaporation

• Electolysis

When ice is heated, it changes to water and water on further heating gets converted to steam. What happens when steam is condensed?

• A new substance is formed

• No new substance is formed

• Gaseous phase changes to liquid phase

• Color Changes

Tags

NGSS.MS-PS1-4

Which of the following will be observed if an apple slice is left exposed to air?

• It under goes oxidation and become brown in colour

• Appearance of brown colour on the surface of apple slice is caused by a chemical reaction between air and enzymes

• It dries up

• None of the options apply

Tags

NGSS.MS-PS1-2

The shipping industry has to bear huge financial loss because of rusting of ships. The rusting of ships occur because:

• The body of ship is always in contact with water

• The air around the ship is humid.

• Presence of salts in sea water speed up the process of rusting.

• The ship is not painted properly

Tags

NGSS.MS-ESS3-3

NGSS.MS-PS1-2

Expansion on heating and contraction on cooling of metals is a

• Chemical Change

• Physical Change

• Irreversible change

• Reversible change

Tags

NGSS.MS-PS1-4

NGSS.MS-PS3-4

Which of the following changes is accompanied by sound?

• Photosynthesis

• Spoilage of food

• Explosion of fire works

• Crumpling of paper