Jatinder Singh Solutions for Chapter: Heat, Exercise 2: TEST YOURSELF

If $10 \mathrm{g}$ of ice at $0°\mathrm{C}$ is mixed with $10 \mathrm{g}$ of water at $10°\mathrm{C}$. What is the temperature of mixing? What is the result of mixing?

Calculate the heat energy required to convert $5 \mathrm{g}$ of ice at $-15°\mathrm{C}$ to steam at $100°\mathrm{C}$.

In an experiment to determine the specific latent heat of fusion of ice '$\mathrm{L}$ by the method of mixtures, the following measurements were taken:

Mass of calorimeter $+$ Stirrer $=x \mathrm{kg}$

Mass of water $=y \mathrm{kg}$

Initial temperature of water $=t_1°\mathrm{C}$

Final temperature of mixture $=t_2°\mathrm{C}$

Mass of ice method $=M \mathrm{kg}$

(Given S.H.C. of calorimeter and water are ${\mathrm{S}}_1$ and $S_{\mathit{2}}$ respectively)

Express $\text{'}\mathrm{L}\text{'}$ in terms of above data.

During the change of state of a substance, the temperature remains unchanged, although the heat is supplied or withdrawn. Explain it on the basis of kinetic theory. Explain the physical difference between solids, liquids and gases on the basis of molecular forces.

Draw a neat and labelled diagram of temperature versus time, when a substance like naphthalene is heated from $0 °\mathrm{C} \mathrm{to} 100 °\mathrm{C}$. Also, draw another curve when the molten substance cools to room temperature. How will you determine the melting point and freezing point from the graphs drawn?

What difference does it make if a calorimeter is made of aluminium instead of copper?

Explain why, with reference to high latent heat of fusion of ice: Rivers fed by water from snow covered mountains are not likely to dry up in summer.

Explain why, with reference to high latent heat of fusion of ice:

Weather may become chilly when snow in the mountains starts melting at the end of the winter season.