Question

Сколько энергии необходимо для превращения 500 г льда, взятого при температуре 0 °С, в воду, имеющую температуру 20 °С? Потерями энергии на нагревание окружающего воздуха пренебречь. Теплоемкость воды 4,18 кДж/кг К. Удельная теплота плавления льда 330 кДж/К. Ответ привести в кДж/К с точностью до четырех значащих цифр. Десятичную дробь записать через запятую.

Answer 1

Qобщ=Qплав+Qнагр воды
Q плав льда = λльда*m
Q нагр воды = cводы*m*Δt где Δt=20-0

Answer 2

Calculation of Energy Required to Convert Ice to Water

To calculate the energy required to convert 500 g of ice at 0 °C to water at 20 °C, we need to consider two processes: the energy required to heat the ice to its melting point and the energy required to melt the ice.

1. Energy required to heat the ice to its melting point: - The specific heat capacity of ice is 2.09 kJ/kg·K. - The initial temperature of the ice is 0 °C, and the final temperature is the melting point of ice, which is 0 °C. - The formula to calculate the energy required is: Q = m × c × ΔT, where Q is the energy, m is the mass, c is the specific heat capacity, and ΔT is the change in temperature. - Substituting the values, we get: Q1 = 500 g × 2.09 kJ/kg·K × (0 °C - 0 °C).

2. Energy required to melt the ice: - The specific latent heat of fusion for ice is 334 kJ/kg. - The formula to calculate the energy required is: Q = m × L, where Q is the energy, m is the mass, and L is the specific latent heat of fusion. - Substituting the values, we get: Q2 = 500 g × 334 kJ/kg.

To find the total energy required, we add the energy required for heating the ice to its melting point and the energy required to melt the ice:

Total energy = Q1 + Q2

Now let's calculate the values:

1. Energy required to heat the ice to its melting point: - Q1 = 500 g × 2.09 kJ/kg·K × (0 °C - 0 °C) = 0 kJ.

2. Energy required to melt the ice: - Q2 = 500 g × 334 kJ/kg = 167,000 kJ.

Therefore, the total energy required to convert 500 g of ice at 0 °C to water at 20 °C is 167,000 kJ.

Please note that the answer is rounded to four significant figures, as requested.