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A liquid at 30°C is poured verly slowly ...

A liquid at 30°C is poured verly slowly into a Calorimeter that is at temperature of 110°C. The boiling temperature of the liquid is 80°C. It is found that the first 5 gm of the liquid completely evaporates. After pouring another 80 gm of the liquid the equilibrium temperature is found to be 50°C. The ratio of the Latent heat of the liquid to its specific heat will be ____C°.
[Neglect the heat exchange with surrounding.]

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To solve the problem, we will analyze the heat exchanges that occur when the liquid is poured into the calorimeter. ### Step-by-Step Solution: 1. **Understanding the Problem:** - We have a liquid at 30°C being poured into a calorimeter at 110°C. - The boiling point of the liquid is 80°C. - The first 5 grams of the liquid completely evaporate. - After pouring an additional 80 grams of the liquid, the equilibrium temperature is found to be 50°C. 2. **Heat Required for Evaporation:** - The first 5 grams of the liquid must be heated from 30°C to 80°C (its boiling point) and then evaporated. - The heat required to raise the temperature of the liquid from 30°C to 80°C: \[ Q_1 = m \cdot c \cdot \Delta T = 5 \, \text{g} \cdot c \cdot (80 - 30) = 5c \cdot 50 = 250c \, \text{(calories)} \] - The heat required for the evaporation of the liquid (latent heat): \[ Q_2 = m \cdot L_v = 5 \cdot L_v \, \text{(calories)} \] 3. **Heat Lost by Calorimeter:** - The calorimeter cools down from 110°C to 80°C while supplying heat to the 5 grams of liquid. - The heat lost by the calorimeter: \[ Q_3 = H \cdot \Delta T = H \cdot (110 - 80) = 30H \] - By the conservation of energy, the heat gained by the liquid equals the heat lost by the calorimeter: \[ Q_1 + Q_2 = Q_3 \] - Substituting the values: \[ 250c + 5L_v = 30H \quad \text{(Equation 1)} \] 4. **Heat Exchange with Additional 80 grams of Liquid:** - The additional 80 grams of liquid is heated from 30°C to 50°C. - The heat gained by the 80 grams of liquid: \[ Q_4 = 80 \cdot c \cdot (50 - 30) = 80c \cdot 20 = 1600c \, \text{(calories)} \] - The calorimeter cools from 80°C to 50°C: \[ Q_5 = H \cdot (80 - 50) = 30H \] - Again, by conservation of energy: \[ Q_4 = Q_5 \] - Substituting the values: \[ 1600c = 30H \quad \text{(Equation 2)} \] 5. **Solving the Equations:** - From Equation 2, we can express \(H\): \[ H = \frac{1600c}{30} = \frac{160c}{3} \] - Substitute \(H\) back into Equation 1: \[ 250c + 5L_v = 30 \left(\frac{160c}{3}\right) \] \[ 250c + 5L_v = 1600c \] \[ 5L_v = 1600c - 250c \] \[ 5L_v = 1350c \] \[ L_v = \frac{1350c}{5} = 270c \] 6. **Finding the Ratio of Latent Heat to Specific Heat:** - The ratio of the latent heat \(L_v\) to the specific heat \(c\): \[ \frac{L_v}{c} = \frac{270c}{c} = 270 \] ### Final Answer: The ratio of the latent heat of the liquid to its specific heat is **270°C**.

To solve the problem, we will analyze the heat exchanges that occur when the liquid is poured into the calorimeter. ### Step-by-Step Solution: 1. **Understanding the Problem:** - We have a liquid at 30°C being poured into a calorimeter at 110°C. - The boiling point of the liquid is 80°C. - The first 5 grams of the liquid completely evaporate. ...
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