Question

8. В калориметр с водой бросают кусочки тающего льда. В некоторый момент кусочки льда перестают таять. Пер воначальная масса воды в сосуде 330 г, а в конце про цесса масса воды увеличивается на 84 г. Какой была начальная температура воды в калориметре? Удельная теплоёмкость воды 4200 Дж/(кг · °С), удельная теплота плавления льда 330 кДж/кг.

Answer 1

В калориметр с водой бросают кусочки тающего льда.лед тает при Т = 0 Св конце процесса таяния масса воды увеличилась на 84 г.значит конечная температура воды Т= 0 Свсе кусочки льда растаяли масса льда  m= 84 г.количество тепла на поглощенное льдом Q=mλλ = 335000 Дж/кгПервоначальная масса воды в сосуде 330 г,масса теплой воды m1 =330 гc1 =4200 Дж/кг*Кначальная температура воды Т1 - ?количество тепла  на плавление льда Q1=с1*m1*(T-T1)уравнение теплового балансаQ +Q1 = 0mλ +с1*m1*(T-T1) = 0mλ = с1*m1*(T1-T)T1-T = mλ / (с1*m1)T1 = Т + mλ / (с1*m1) = 0 +84* 335000 / (4200*330) = 20 СОТВЕТ  20 С.

Answer 2

Calculating the Initial Temperature of Water in the Calorimeter

To calculate the initial temperature of the water in the calorimeter, we can use the principle of conservation of energy. When the ice melts, it absorbs heat from the water in the calorimeter, causing the temperature of the water to decrease until the ice stops melting. At this point, the heat gained by the ice is equal to the heat lost by the water. We can use the following equation to calculate the initial temperature of the water:

Q_lost = Q_gained

Where: - Q_lost is the heat lost by the water - Q_gained is the heat gained by the ice

The heat lost by the water can be calculated using the formula:

Q_lost = m_water * c_water * ΔT

Where: - m_water is the mass of water - c_water is the specific heat capacity of water - ΔT is the change in temperature

The heat gained by the ice can be calculated using the formula:

Q_gained = m_ice * L_f

Where: - m_ice is the mass of ice - L_f is the specific latent heat of fusion for ice

By setting these two equations equal to each other, we can solve for the initial temperature of the water.

Calculation

Given: - Initial mass of water (m_water) = 330 g - Final increase in mass of water = 84 g - Specific heat capacity of water (c_water) = 4200 J/(kg·°C) - Specific latent heat of fusion for ice (L_f) = 330 kJ/kg

First, we need to convert the masses to kilograms: - Initial mass of water = 330 g = 0.33 kg - Final mass of water = (330 + 84) g = 0.414 kg

Now, we can calculate the heat lost by the water: Q_lost = m_water * c_water * ΔT Q_lost = (0.33 kg) * (4200 J/kg·°C) * ΔT

The heat gained by the ice is equal to the heat lost by the water: Q_gained = Q_lost

We can now solve for the initial temperature (ΔT) using the given values.

Solution

Using the given values and the equations above, we can solve for the initial temperature of the water in the calorimeter.