Chemistry Quiz Basic MCQ! Exam

Explanation
When ice melts, its temperature remains constant because the heat energy being absorbed is used to break the intermolecular bonds between the water molecules rather than increasing the temperature. This process is known as the latent heat of fusion. Once all the ice has melted and the bonds are broken, the temperature can start to increase again.

Explanation
The correct answer is 80 cal/gm. The latent heat of fusion of ice refers to the amount of heat energy required to change a unit mass of ice at its melting point into water at the same temperature. In this case, the value is given in calories per gram, indicating that 80 calories of heat energy are needed to convert 1 gram of ice into water at 0°C.

Explanation
To convert temperature from Kelvin to Celsius, we need to subtract 273 from the given temperature. In this case, when we subtract 273 from 330K, we get 57°C. Therefore, the temperature of the steel rod is 570°C.

Explanation
The boiling point of water at 1 atm is 100K. This is the correct answer because the boiling point of water is 100 degrees Celsius or 373 Kelvin at standard atmospheric pressure of 1 atmosphere (1 atm). The options 2730C, 373 K, and 3073K are incorrect as they do not represent the correct boiling point of water at 1 atm.

Explanation
When water is boiling at 100oC, it is in its gaseous state and has a high amount of thermal energy. When it condenses back into liquid form at the same temperature, this thermal energy is released. The amount of energy released when 1gm of water condenses at 100oC is 540 Cal. This is calculated using the specific heat capacity of water and the latent heat of vaporization.

Explanation
Water has a greater specific heat value compared to kerosene, oil, and diesel. Specific heat is the amount of heat energy required to raise the temperature of a substance by a certain amount. Water has a high specific heat because it can absorb and retain a large amount of heat energy without a significant increase in temperature. This property of water is important for regulating temperature in the environment and in living organisms. Kerosene, oil, and diesel have lower specific heat values, meaning they require less heat energy to raise their temperature compared to water.

Explanation
When water freezes, it undergoes a phase change and transforms from a liquid to a solid state. During this process, the water molecules arrange themselves in a more structured pattern, forming a crystal lattice. This arrangement leads to an increase in volume compared to the liquid state. Therefore, the volume of water increases when it freezes.

Explanation
The SI unit of specific heat is J/Kg-K. This unit represents the amount of energy required to raise the temperature of one kilogram of a substance by one degree Kelvin. It is a measure of the substance's ability to store and release heat energy.

Explanation
Water is commonly used as a coolant due to its high specific heat capacity and thermal conductivity. It can absorb and transfer heat effectively, making it suitable for cooling various systems and machinery. Water is also readily available and cost-effective compared to other options like kerosene or air. Additionally, water has a high boiling point, which allows it to absorb a significant amount of heat before evaporating. This property makes it particularly useful in applications where high temperatures need to be controlled or dissipated.

Explanation
During evaporation, the temperature falls. This is because the process of evaporation requires energy, which is obtained from the surrounding environment. As the liquid molecules gain energy and escape into the air as vapor, they take away some of the heat from the remaining liquid, causing a decrease in temperature. This is why we feel a cooling effect when a liquid evaporates, such as when sweat evaporates from our skin.