The amount of heat needed to heat 200 grams of ice at $-10^{\circ} \mathrm{C}$ to convert it into water at…

The amount of heat needed to heat 200 grams of ice at $-10^{\circ} \mathrm{C}$ to convert it into water at $30^{\circ} \mathrm{C}$ is Specific heat capacity of ice $=2100 \mathrm{~J} \mathrm{~kg}^{-1} \mathrm{~K}^{-1}$ Specific heat capacity of water $=4186 \mathrm{~J} \mathrm{~kg}^{-1} \mathrm{~K}^{-1}$ Latent heat of fusion of ice $=3.35 \times 10^5 \mathrm{~J} \mathrm{~kg}^{-1}$
  1. $96316 \mathrm{~J}$
  2. $67000 \mathrm{~J}$
  3. $92116 \mathrm{~J}$
  4. $71200 \mathrm{~T}$

Solution

We have $\Delta \mathrm{Q}=\mathrm{mS}_{\mathrm{i}}\left[-10^{\circ}-0^{\circ}\right]-\mathrm{mL}_{\mathrm{f}}+\mathrm{mS}_{\mathrm{w}}\left[0^{\circ}-30^{\circ}\right]$ $\begin{aligned} & =-\mathrm{mS}_{\mathrm{i}}\left(+10^{\circ}\right)-\mathrm{mL}_{\mathrm{f}}-\mathrm{mS}_{\mathrm{w}}\left(30^{\circ}\right) \\ & =-0.2 \times 2100 \times 10-0.2 \times 3.35 \times 10^5-0.2 \times 4186 \times 30 \\ & =-96316 \mathrm{~J}\end{aligned}$ -ve sign indicate that heat is absorbed So, $\Delta Q_{\text {absorbed }}=96316 \mathrm{~J}$

Asked in: AP EAMCET 2022 (05 Jul Shift 2)

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