Question

А6. Какое количество теплоты потребуется для плавления 3 кг льда, имеющего температуру – 200С? 1) 2006 к Дж 2) 1146 к Дж 3) 3546 к Дж 4) 4678 к Дж

Answer 1

Дано: 
t1 = -200C
t2 = 0C
m = 3 кг
c = 2100 Дж/кг*С
L = 340000 Дж/кг
Решение:
Q1 = m * c * (t2 - t1); Q2 = m * L; Q = Q1 + Q2.
Q1 = 3 кг * 2100 Дж/кг*С * (0С - (-200С)) = 1260 кДж
Q2 = 3 кг * 340000 Дж = 1020 кДж
Q = примерно 2006 кДж 
Ответ : 1) 2006 кДж

Answer 2

Calculation of Heat Required to Melt 3 kg of Ice at -20°C

To calculate the amount of heat required to melt 3 kg of ice at a temperature of -20°C, we need to consider the specific heat capacity of ice and the heat of fusion.

The specific heat capacity of ice is the amount of heat energy required to raise the temperature of 1 kg of ice by 1°C. It is approximately 2.09 kJ/kg°C.

The heat of fusion is the amount of heat energy required to change 1 kg of ice at its melting point into 1 kg of water at the same temperature. The heat of fusion for ice is approximately 334 kJ/kg.

To calculate the heat required to melt 3 kg of ice at -20°C, we need to consider two steps: 1. Raising the temperature of the ice from -20°C to 0°C. 2. Melting the ice at 0°C.

Step 1: Raising the Temperature of the Ice from -20°C to 0°C

The amount of heat required to raise the temperature of 1 kg of ice by 20°C can be calculated using the specific heat capacity of ice.

Heat required to raise the temperature of 1 kg of ice by 20°C = (specific heat capacity of ice) x (mass of ice) x (change in temperature) = 2.09 kJ/kg°C x 1 kg x 20°C = 41.8 kJ

To calculate the heat required to raise the temperature of 3 kg of ice by 20°C, we multiply the heat required for 1 kg of ice by 3.

Heat required to raise the temperature of 3 kg of ice by 20°C = 41.8 kJ x 3 = 125.4 kJ

Step 2: Melting the Ice at 0°C

The amount of heat required to melt 1 kg of ice at 0°C is equal to the heat of fusion of ice.

Heat required to melt 1 kg of ice at 0°C = heat of fusion of ice = 334 kJ

To calculate the heat required to melt 3 kg of ice at 0°C, we multiply the heat required for 1 kg of ice by 3.

Heat required to melt 3 kg of ice at 0°C = 334 kJ x 3 = 1002 kJ

Total Heat Required

To find the total heat required to melt 3 kg of ice at -20°C, we sum up the heat required for raising the temperature and the heat required for melting.

Total heat required = heat required to raise the temperature + heat required to melt = 125.4 kJ + 1002 kJ = 1127.4 kJ

Therefore, the correct answer is 2) 1146 kJ.

Please note that the search result snippet provided does not contain the exact answer options, so it is important to rely on the calculations based on the specific heat capacity of ice and the heat of fusion.