Give two example to prove that heat energy brings about a chemical change.
Answer
Burning of substances like charcoal, paper or wood undergo a chemical change and gives carbon dioxide gas and water vapor with the release of large amounts of heat energy.
Given below statement is incorrect. Write the correct statement : One joule is the amount of energy required to raise the temperature of 1 g water through $1^{\circ} C$.
Answer
One joule is the amount of energy required to raise the temperature of 1 g water by $1^{\circ} C$.
Given below statement is incorrect. Write the correct statement : The fixed temperature at which a solid changes into liquid state with the release of heat energy is called melting point.
Answer
The fixed temperature at which a solid changes into liquid state with the absorb of heat energy is called melting point.
Given below statement is incorrect. Write the correct statement : The freezing point of a liquid and melting point of a solid of same material have different numerical values.
Answer
The freezing point of a liquid and melting point of a solid of same material have same numerical values.