matter in our surrounding

When a gas jar full of air is placed upside down on a gas jar full of bromine vapours, the red-brown vapours of bromine from the lower jar go upward into the jar containing air. In this experiment:

• Air is heavier than bromine

• Both air and bromine have the same density

• Bromine is heavier than air

• Bromine cannot be heavier than air because it is going upwards against gravity

A form of matter has no fixed shape but it has a fixed volume. An example of this form of matter is

• Krypton

• Kerosene

• Carbon steel

• Carbon dioxide

Which one of the following statements is not true?

• The molecules in a solid vibrate about a fixed position

• The molecules in a liquid are arranged in a regular pattern

• The molecules in a gas exert negligibly small forces on each other, except during collisions

• The molecules of a gas occupy all the space available

The correct procedure of heating iron-sulphur mixture to prepare iron sulphide is: :

• Heat the powder mixture at the base of the test tube using a blue flame throughout.

• Heat the iron filings and sulphur mixture in the middle of the test tube using yellow flame throughout.

• Heat the powder mixture at the top of the test tube using an orange flame throughout.

• Heat the iron filings-sulphur mixture at 3/4 quarters of the test tube using a red flame throughout.

When water at 0°C freezes to form ice at the same temperature of 0°C, then it:

• Absorbs some heat

• Releases some heat

• Neither absorbs nor releases heat

• Absorbs exactly 3.34 x 10⁵J/kg of heat

When heat is constantly supplied by a burner to boiling water, then the temperature of water during vaporisation :

• Rises very slowly

• Absorbs some heat

• Rises rapidly until steam is produced

• Does not rise at all

Which one of the following set of phenomena would increase on raising the temperature?

• Diffusion, evaporation, compression of gases

• Evaporation, compression of gases, solubility

• Evaporation, diffusion, expansion of gases

• Evaporation, solubility, diffusion, compression of gases

On converting 308 K, 329 K and 391 K to Celsius scale, the correct sequence of temperatures will be:

• 33°C, 56°C and 118°C

• 35°C, 56°C and 119°C

• 35°C, 56°C and 118°C

• 56°, 119°C and 35° C

Which of the following phenomena always results in the cooling effect?

• Condensation

• Evaporation

• Sublimation

• None of these

Which of the following cannot be considered a form of matter?

• Atom

• Water

• Humidity

• Electron