Question

ПОМОГИТЕ ПОЖАЛУЙСТА! 1.117. Определите количество теплоты, необходимое для плавления 2,4 кг свин итого при з того при его температуре плавлення.1.118. Какая масса алюминия, кристаллизуясь без изменения температуры, выделяет 114 кДж тепла?1.119. Для плавления тела массой 0,3 кг без изменения температуры потребова вось количество теплоты, равнос 17.7 кДж. Определите удельгую теплоту плавле вещества, из которого состоит тело. Как называется это вещество, чему равна ем температура плавления?​

Answer 1

Ответ: 1. 0,6x$10^{5}$ 2. 3,42кг 3. 5310 Дж/кг

Объяснение:

1/117 Q=λm(плавление)

Дано:

m=2,4 кг

λ=0,25x$10^{5}$

Q= 2,4x(0,25x10(5ст.) = 0,6x$10^{5}$

1.118 Q=-λm(Кристаллизация) m= Q/λ

Дано: λ= 3,9x$10^{5}$

Q= 114000 Дж

m =  3,9x$10^{5}$/114000 = 3,42кг

1.119 Q = λm λ=Q/m

m =0,3кг

Q= 17.7 кДж

λ = ?

λ= 17700x0,3 = 5310 Дж/кг

Answer 2

Calculation of Heat Required for Melting Lead

To determine the amount of heat required to melt 2.4 kg of lead at its melting temperature, we need to use the specific heat of lead and the heat of fusion.

The specific heat capacity of lead is approximately 0.13 J/g°C, and the heat of fusion for lead is approximately 24.5 kJ/kg [[1]].

First, we need to calculate the heat required to raise the temperature of the lead from its initial temperature to its melting temperature. Since the temperature is not specified, we'll assume it is at room temperature (around 25°C).

The formula to calculate the heat required to raise the temperature of a substance is:

Q = m * c * ΔT

Where: - Q is the heat required (in joules) - m is the mass of the substance (in grams) - c is the specific heat capacity of the substance (in J/g°C) - ΔT is the change in temperature (in °C)

Let's calculate the heat required to raise the temperature of the lead:

Q1 = 2.4 kg * 1000 g/kg * 0.13 J/g°C * (Pb_melting_temperature - 25°C)

Next, we need to calculate the heat required for the phase change (melting) of the lead. The formula to calculate the heat required for a phase change is:

Q2 = m * ΔHf

Where: - Q2 is the heat required for the phase change (in joules) - m is the mass of the substance (in kilograms) - ΔHf is the heat of fusion (in J/kg)

Let's calculate the heat required for the phase change of the lead:

Q2 = 2.4 kg * 24.5 kJ/kg * 1000 J/kJ

Finally, we can calculate the total heat required for melting the lead:

Total heat = Q1 + Q2

Please note that the specific heat capacity and heat of fusion values used here are approximate and may vary slightly depending on the source.