Question

Физику совсем не понимаю, дали задание, я нашла ответы дома, а сейчас просят сказать формулы по которым я находила их 1) Какая энергия выделится при отвердевании аллюминия массой 1 кг? 2) Какая энергия выделится при кристаллизации аллюминия массой 20 кг? 3) Какая энергия требуется для плавления аллюминия массой 200 кг, имеющего температуру 20 градусов? 4) Какая энергия выделится при конденсации водяного пара массой 0,5 кг при температуре 100 градусов?

Answer 1

1)
Q=лm где л(лямбда) -удельная теплота плавления аллюминия
л=390*10^3 дж/ru
Q =390 000 Дж

2)та же формула
Q = 20 * 390 000 = 7800 000 Дж или 7.8 МДж

3)
здесь сначала нагреваем аллюминий до температуры плавления 
Q1 = cm(t2-t1) - с - удельная теплоемкость (900Дж\кг*градус)
алюминий плавится при т=660
Q1=900*200*(660-20)=115200000 Дж или 115.2 МДж
далее - плавим Q2=лm= 200*390 000=78MДж
Суммируем энергию: Q1+Q2= 183.2МДж

4)
Q=Lm L- удельная теплота парообразования
у воды - L= 2256 000 Дж
Q= 2256000*0.5=1128 000 Дж или 1.128МДж

Answer 2

Energy Released during Solidification of Aluminum

The energy released during the solidification of aluminum can be calculated using the formula:

Q = m * L

Where: - Q is the energy released (in joules) - m is the mass of aluminum (in kilograms) - L is the latent heat of solidification of aluminum (in joules per kilogram)

To find the energy released during the solidification of aluminum with a mass of 1 kg, we need to know the latent heat of solidification of aluminum. The latent heat of solidification for aluminum is approximately 397 kJ/kg [[1]].

Substituting the values into the formula, we get:

Q = 1 kg * 397,000 J/kg = 397,000 J

Therefore, the energy released during the solidification of aluminum with a mass of 1 kg is 397,000 joules.

Energy Released during Crystallization of Aluminum

The energy released during the crystallization of aluminum can also be calculated using the formula:

Q = m * L

Where: - Q is the energy released (in joules) - m is the mass of aluminum (in kilograms) - L is the latent heat of crystallization of aluminum (in joules per kilogram)

To find the energy released during the crystallization of aluminum with a mass of 20 kg, we need to know the latent heat of crystallization of aluminum. The latent heat of crystallization for aluminum is approximately 397 kJ/kg [[1]].

Substituting the values into the formula, we get:

Q = 20 kg * 397,000 J/kg = 7,940,000 J

Therefore, the energy released during the crystallization of aluminum with a mass of 20 kg is 7,940,000 joules.

Energy Required for Melting Aluminum

The energy required for melting aluminum can be calculated using the formula:

Q = m * L

Where: - Q is the energy required (in joules) - m is the mass of aluminum (in kilograms) - L is the latent heat of fusion of aluminum (in joules per kilogram)

To find the energy required for melting aluminum with a mass of 200 kg, we need to know the latent heat of fusion of aluminum. The latent heat of fusion for aluminum is approximately 397 kJ/kg [[1]].

Substituting the values into the formula, we get:

Q = 200 kg * 397,000 J/kg = 79,400,000 J

Therefore, the energy required for melting aluminum with a mass of 200 kg is 79,400,000 joules.

Energy Released during Condensation of Water Vapor

The energy released during the condensation of water vapor can be calculated using the formula:

Q = m * L

Where: - Q is the energy released (in joules) - m is the mass of water vapor (in kilograms) - L is the latent heat of condensation of water (in joules per kilogram)

To find the energy released during the condensation of water vapor with a mass of 0.5 kg, we need to know the latent heat of condensation of water. The latent heat of condensation for water is approximately 2,260 kJ/kg [[2]].

Substituting the values into the formula, we get:

Q = 0.5 kg * 2,260,000 J/kg = 1,130,000 J

Therefore, the energy released during the condensation of water vapor with a mass of 0.5 kg is 1,130,000 joules.

Note: The values provided are approximate and may vary depending on the specific conditions and purity of the substances involved.

[[1]] Source: [Engineering Toolbox - Latent Heat of Fusion and Latent Heat of Solidification](https://www.engineeringtoolbox.com/latent-heat-fusion-d_1265.html) [[2]] Source: [Engineering Toolbox - Latent Heat of Vaporization and Latent Heat of Condensation](https://www.engineeringtoolbox.com/latent-heat-vaporization-d_1479.html)