Questions
Which of the following is a desirable change?
- Burning of House
- Floods
- Landslides
- Burning of cooking gas
Which of the following is an example of periodic change?
- Eruption of volcano
- Heartbeat
- A car accident
- Landslide
(NCERT): Salt can be separated from its solutions (Salt dissolved in water), because
- Mixing of salt in water in a change that can be reversed by heating and melting of salt.
- Mixing of salt in water is a change that cannot be reversed.
- Mixing of salt in water is a permanent change.
- Mixing of salt in water is a change that can be reversed by evaporation.
Changes in which heat is liberated are called ____________
- Exothermic changes
- Endothermic changes
- Rapid changes
- None of these
Iodine sublimes on heating i.e. directly changes into a gas state without going through liquid state . Which of the following change is not true for iodine sublimation?
- Change is fast
- Change is physical
- Change is chemical
- Change is reversible
Which of the following is a reversible change?
- Curding of milk
- Ripening of fruits
- Melting of ice
- Burning of wood
Which of the following can be considered as fast change?
- Growth of child
- Germination of seed
- Bursting of crackers
- Cooking of food
Souring of milk is a
- Undesirable change
- Desirable change
- Physical change
- Periodic change
Burning of candle is
- Physical change
- Chemical change
- Both physical and chemical change
- Neither physical and chemical change
Baking of dough into bread is a kind of change
- That can be reversed
- That cannot be reversed
- That can be reversed at very hot temperature
- Can't say
In chemical change
- Molecules of the substance do not change
- Molecules of a substance change
- Substance remain same
- Change is reversible
(NCERT): Iron rim is made slightly smaller than the wooden wheel. The rim is usually heated before fixing into the wooden wheel, because on heating the iron rim
- Expands and fits onto the wooden wheel.
- Contacts and fits onto the wooden wheel.
- No change in the size takes place.
- Expands first, then on cooling contracts and fits onto the wooden wheel.
The process of converting gas into liquid is called
- Freezing
- Cooling
- Condensation
- Evaporation
Chemical changes are
- Always reversible
- Always are irreversible
- Mostly irreversible
- D. Mostly reversible
Electric wires or telephone wire became tight during winter and sag a little during summers because metal
- Expand on heating
- Remain same on heating
- Contract on heating
- Change in shape on heating.
Which of the following is an example of physical change?
- A bud turning into flower
- Rusting of iron
- Ripening of fruit
- Boiling of Water
Which one is a periodic change
- Melting of ice
- Change in season
- Dissolving sugar in water
- Rusting of iron
In a chemical change
- Energy is either absorbed or given out.
- Energy is always absorbed
- Energy is given out
- Energy change do not occur
In general, on heating metals__________
- Contact
- Expand
- Can expand or contract
- None of these
The product formed by dissolving a substance into another is called
- Compound
- Solution
- Solvent
- Solute