Question

3. При сгорании пороха массой 3 кг выделилось 11 40ОкДж энергии. Вычислите удельную теплоту сгорания пороха. 4. Смешали бензин объемом 1,5л и спирт массой 3 кг. Какое количество теплоты выделится при полном сгорании полученной смеси? 5. Сколько каменного угля нужно сжечь, чтобы получить столько же энергии, сколько ее выделится при сгорании бензина объемом 6 м??

Answer 1

Ответ:

Q=38000кДж

Масса-?

Удельная теплота сгорания пороха (С) =3800кДж,

Q=С\m.

m=С\Q

Значит

38000(кДж) /3800(кДж/кг) =10кг.

Answer 2

Calculation of Specific Heat of Combustion of Gunpowder

To calculate the specific heat of combustion of gunpowder, we need to use the given information that 3 kg of gunpowder released 11,400 kJ of energy.

The specific heat of combustion (also known as the heat of combustion per unit mass) is the amount of heat released when a substance undergoes complete combustion per unit mass. It is typically measured in units of energy per unit mass, such as kJ/kg or J/g.

To calculate the specific heat of combustion, we can use the formula:

Specific Heat of Combustion = Energy Released / Mass of Substance

In this case, the energy released is 11,400 kJ and the mass of the gunpowder is 3 kg. Plugging these values into the formula, we get:

Specific Heat of Combustion = 11,400 kJ / 3 kg

Calculating this, we find that the specific heat of combustion of the gunpowder is:

Specific Heat of Combustion = 3,800 kJ/kg

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Calculation of Heat Released by Mixing Gasoline and Alcohol

To calculate the amount of heat released when gasoline and alcohol are completely burned, we need to consider the energy content of each fuel and the amounts used.

Given that we have 1.5 liters of gasoline and 3 kg of alcohol, we need to determine the energy content of each fuel and then calculate the total energy released.

The energy content of gasoline is typically around 31.4 MJ/liter, while the energy content of alcohol (ethanol) is approximately 29.7 MJ/kg.

To calculate the energy released by burning the gasoline, we multiply the volume (1.5 liters) by the energy content (31.4 MJ/liter):

Energy Released by Gasoline = 1.5 liters * 31.4 MJ/liter

To calculate the energy released by burning the alcohol, we multiply the mass (3 kg) by the energy content (29.7 MJ/kg):

Energy Released by Alcohol = 3 kg * 29.7 MJ/kg

Finally, we can calculate the total energy released by summing the energy released by the gasoline and the alcohol:

Total Energy Released = Energy Released by Gasoline + Energy Released by Alcohol

Calculating this, we can determine the amount of heat released by the mixture.

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Calculation of Coal Required to Produce the Same Energy as 6 Liters of Gasoline

To calculate the amount of coal required to produce the same amount of energy as 6 liters of gasoline, we need to consider the energy content of coal and gasoline.

The energy content of gasoline is typically around 31.4 MJ/liter, as mentioned earlier.

The energy content of coal can vary depending on the type and quality of the coal. On average, bituminous coal has an energy content of about 24-35 MJ/kg.

To calculate the energy released by burning 6 liters of gasoline, we multiply the volume (6 liters) by the energy content (31.4 MJ/liter):

Energy Released by Gasoline = 6 liters * 31.4 MJ/liter

To calculate the mass of coal required to produce the same amount of energy, we need to convert the energy content of coal from MJ/kg to MJ/liter. Assuming an average energy content of 30 MJ/kg for coal, we can calculate the mass of coal required as follows:

Mass of Coal Required = Energy Released by Gasoline / Energy Content of Coal

Calculating this, we can determine the amount of coal required.

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