Effects of Heat: Increase in Temperature

What is heat energy, and what are its effects?

Heat energy produces increase in temperature.

Define temperature.

A solid is heated up and $\Delta \text{H}$ vs $\Delta \theta$($∆H :$Heat given, $∆\theta :$change in temperature) is plotted as shown in figure. Material exist in only one phase in-

When 100 mL of 1.0 M HCl was mixed with 100 mL of 1.0 M NaOH in an insulated beaker at constant pressure, a temperature increase of $5.7{ }^{\mathrm{o}}\mathrm{C}$ was measured for the beaker and its contents (Expt.1). Because the enthalpy of neutralisation of a strong acid with a strong base is a constant $(-57.0\mathrm{ }\mathrm{k}\mathrm{J}\mathrm{ }\mathrm{m}\mathrm{o}{\mathrm{l}}^{-1})$, this experiment could be used to measure the calorimeter constant. In a second experiment (Expt. 2), 100 mL of 2.0 M acetic acid $({\mathrm{K}}_{\mathrm{a}}=2.0\times {10}^{-5})$ was mixed with 100 mL of 1.0 M NaOH (under identical conditions to Expt. 1) where a temperature rise of $5.6{ }^{\mathrm{o}}\mathrm{C}$ was measured.

(Consider heat capacity of all solutions as $4.2\mathrm{ }\mathrm{J}\mathrm{ }{\mathrm{g}}^{-1}\mathrm{ }{\mathrm{K}}^{-1}$ and density of all solutions as $1.0\mathrm{ }\mathrm{g}\mathrm{ }\mathrm{m}{\mathrm{L}}^{-1}$ )

Enthalpy of dissociation $\left(\mathrm{i}\mathrm{n}\mathrm{ }\mathrm{k}\mathrm{J}\mathrm{ }\mathrm{m}\mathrm{o}{\mathrm{l}}^{-1}\right)$ of acetic acid obtained from the Expt. 2 is

Two spheres made of the same substance, have diameters in the ratio $1:2$. Their thermal capacities are in the ratio of

If $70 \mathrm{cal}$  of heat is required to raise the temperature of $2$ moles of an ideal gas at constant pressure from $30\mathrm{℃}$ to $35\mathrm{℃}$, then the amount of heat required to raise the temperature of same gas through same range at constant volume is

The specific heat capacity of a metal at low temperature ($T$) is given as $C_p\left(\mathrm{k}\mathrm{J}{\mathrm{K}}^{-1}\mathrm{k}{\mathrm{g}}^{-1}\right)=32{\left(\frac{T}{400}\right)}^3.$ A 100 g vessel of this metal is to be cooled from 20 K to 4 K by a special refrigerator operating at room temperature $\left(27℃\right).$ The amount of work required to cool the vessel is

Amount of heat required to convert 10 g of ice to water at 20$℃$ is

Water falls from a height of $500 \mathrm{m}$. What is the rise in temperature of water at the bottom if whole energy is used up in heating water?

If the ratio of densities of two substances is $5 :6$ and that of the specific heats is $3 :5$. Then the ratio between heat capacities per unit volume is

Water of volume 2 L in a closed container is heated with a coil of 1 kW. While water is heated, the container loses energy at a rate of 160 J/s. In how much time will the temperature of water rise from 27^oC to 77^oC ? (Specific heat of water is 4.2 kJ/kg and that of the container is negligible).

The ratio of thermal capacities of two spheres $A$ and $B$, if their diameters are in the ratio $1:2$, densities in the ratio $2:1$, and the specific heat in the ratio of$1:3$, will be

Heat given to a body which raises its temperature by 1^oC is