$100\,g$ of water is supercooled to $-\,10\,^oC$. At this point, due to some disturbance mechanised or otherwise some of it suddenly freezes to ice. What will be the temperature of the resultant mixture and how much mass would freeze ? $[S_W = 1\,cal\,g^{-1}\,^oC^{-1}$ and ${L^W}_{{\text{fussion}}}$ $= 80\,cal\,g^{-1}]$
Mass of water $m=100 \mathrm{~g}$
Change in temperature $\Delta \mathrm{T}=0-(-10)=10^{\circ} \mathrm{C}$
Specific heat of water $\mathrm{s}_{\mathrm{w}}=1$ calg $^{-1}{ }^{\circ} \mathrm{C}^{-1}$
Latent heat of melting of water $\mathrm{L}_{f}=80$ calg $^{-1}$
Heat required to convert ice at $-10^{\circ} \mathrm{C}$ to $0^{\circ} \mathrm{C}$ water.
$\mathrm{Q}=m \mathrm{~s}_{\mathrm{w}} \Delta \mathrm{T}$ $=100 \times 1 \times 10$ $=1000 \text { cal }$
Suppose, ' $m$ ' gram ice melt,
$\therefore \quad \mathrm{Q}=m \mathrm{~L}$
$m=\frac{\mathrm{Q}}{\mathrm{L}}$
$=\frac{1000}{80}$
$=12.5 \mathrm{~g}$
As only $12.5 \mathrm{~g}$ ice is melted from $100 \mathrm{~g}$, the temperature of mixture will be $0^{\circ} \mathrm{C}$.
A copper block of mass $5.0\, kg$ is heated to a temperature of $500^{\circ} C$ and is placed on a large ice block. What is the maximum amount of ice (ઇન $kg$) that can melt? [Specific heat of copper: $0.39\, Jg ^{-1 \circ} C ^{-1}$ and latent heat of fusion of water : $335 \,J g ^{-1}$ ]
In a calorimeter of water equivalent $20 \,g$, water of mass $1.1 \,kg$ is taken at $288 \,K$ temperature. If steam at temperature $373 \,K$ is passed through it and temperature of water increases by $6.5^{\circ} C$ then the mass of steam condensed is ............ $g$
$5\,\,gm.$ of ice at $0\,^oC$ is dropped in a beaker containing $20\,\,gm.$ of water at $40\,^oC.$ The final temperature will be ........ $^oC$
$20\, gm$ of boiling water is poured into an ice-cold brass vessel (specific heat $0.1\, cal/gm-\,^oC$) of mass $100\, gm$. The resulting temperature is ........ $^oC$
Calorie is defined as the amount of heat required to raise temperature of $1g$ of water by $1°C$ and it is defined under which of the following conditions