Constant Temperature During Melting
The temperature of ice stays constant at its melting point (0°C or 32°F) while it is melting because the absorbed heat energy is used for the phase change from solid to liquid, not to increase the temperature.
Latent Heat and Molecular Bonds
This phenomenon is explained by the concept of latent heat of fusion. The heat absorbed during melting is called latent heat. This energy is specifically used to overcome the intermolecular forces (bonds) holding the water molecules in a fixed crystalline structure (ice).
- Heat Absorption: Ice absorbs heat energy from the surroundings.
- Energy Use: Instead of increasing the kinetic energy of the molecules (which would raise the temperature), the absorbed energy is used to break the bonds between molecules.
- Phase Change: This bond-breaking process allows the molecules to move more freely, transitioning from the solid state (ice) to the liquid state (water).
- Constant Temperature: As long as both ice and water are present and the phase change is occurring, the temperature remains fixed at the melting point. Once all the ice has melted, any further heat absorbed will increase the temperature of the liquid water.
Evaluating Other Options
- Option 1 is incorrect because heat absorption *causes* melting.
- Option 2 is incorrect; while ice density is relevant to its properties, it doesn't explain the constant temperature during melting.
- Option 4 is incorrect; heat absorption is the key process, not reflection.
Therefore, the primary reason the temperature remains constant is that the heat energy is utilized to break the intermolecular bonds.
Important Questions from Physics
What is the colour of the light emitted by the Sun?
Lightning occur in the sky when two clouds:
With reference to street-lighting, how do sodium lamps differ from LED lamps?
1. Sodium lamps produce light in 360 degrees but it is not so in the case of LED lamps.
2. As street lights, sodium lamps have a longer life span than LED lamps.
3. The spectrum of visible light from sodium lamps is almost monochromatic while LED lamps offer significant colour advantages in street lighting.
Select the correct answer using the code given below.
Which one of the following is a reason why astronomical distances are measured in light-years?
In a pressure cooker, the temperature at which the food is cooked depends mainly upon which of the following?
1. Area of the hole in the lid
2. Temperature of the flame
3. Weight of the lid
Select the correct answer using the code given below.
