Phase Transition | MCQs

Explanation

When a gas changes into a liquid, the molecules:

• Move closer together (their distance decreases)
• Lose kinetic energy (they slow down)

Explanation

Condensing is the process by which a gas changes state to become a liquid.

This occurs when the temperature and pressure of the gas are reduced to the point where the molecules slow down and come together to form a liquid.

Key Points:

• Melting is the process where a solid becomes a liquid.
• Freezing is the process where a liquid becomes a solid.
• Boiling is the process where a liquid becomes a gas.

Explanation

• Freezing is the process by which a liquid changes to a solid.
• It is the reverse of melting, which is the process by which a solid changes to a liquid.

Explanation

• A change in physical appearance or state of a substance, such as a change in shape, size, color, or phase (solid, liquid, gas), is called a Physical Change.
  

The are examples of Physical Changes:

• Melting (ice cream, wax, chocolate, ice and change from solid to liquid)
• Phase changes (boiling, freezing, condensation)
• Crushing (chalk)
• Tearing (paper)
• Crumpling (aluminium foil)
• Stretching (rubber band)
• Mixing (sugar in water)
• Dissolving (sugar, salt in water)
• Moulding (clay, metals)
• Slicing (fruit)
• Forming of frost (from water vapors)
• Transition to a gas (change from liquid to gas)
• Change of durability (change in texture or strength)
• Changes to crystal form (change in crystal structure)

Explanation

A change in physical appearance or state of a substance, such as a change in shape, size, color, or phase (solid, liquid, gas), is called a Physical Change.

Explanation

• A release of gas is typically a sign of a chemical change, not a physical change.

The signs of physical change:

• Change that can be reversed
• The substance does not turn into a new substance

Explanation

• Sublimation is the transition of a substance from the solid to the gas phase without going through the liquid phase.
• This means that a solid changes directly into a gas, without first melting into a liquid.

Explanation

• Liquids can be converted into solids by cooling, a process known as freezing or solidification.
• As the temperature decreases, the particles of the liquid slow down and come together, forming a solid.

Explanation

• Liquids can be converted into gases by heating, a process known as vaporization or evaporation.
• As the temperature increases, the particles of the liquid gain energy and move faster, eventually breaking free from the surface tension of the liquid and turning into a gas.

Explanation

• Solids can be converted into liquids by heating, a process known as melting.
• This occurs when the particles of the solid gain enough energy to break free from their fixed positions and start moving freely, resulting in a liquid state.