Question

Яка енергія виділяться внаслідок повного згоряння 3 дм(кубічних) гасу? Какая энергия выделятся в результате полного сгорания 3 дм (куб) керосина? На скільки градусів можна нагріти воду обємом 130 л спаливши 2,1 кг сухих дров якщо вважати що вся тепло а піде на нагрівання води На сколько градусов можно нагреть воду объемом 130 л сжег 2,1 кг сухих дров если считать что все тепло а пойдет на нагрев воды

Answer 1

Энергия которая выделится при полном сгорании 3 дм³ = 0,003 м³ будет: 
удельная теплота сгорания керосина 46·10⁶ Дж/кг: плотность керосина 800 кг/м³;
        $Q=q\cdot m=q\cdot \rho\cdot V=46\cdot 10^6\cdot 800\cdot 0,003=1104\cdot 10^5$ Дж

Если всё тепло при сгорании идёт на нагревании воды тогда: 
      $Q_1=Q_2 \\ c\cdot m\cdot зt=q\cdot m$
Откуда величина на которую нагреется вода: 
      $зt= \frac{q\cdot m_2}{c\cdot m_1}= \frac{q\cdot m_2}{c\cdot \rho_1\cdot V_1}$
удельная теплота сгорания сухих дров 1·10⁷ Дж/кг; удельная теплоёмкость воды 4200 Дж/кг·°С; плотность воды 1000 кг/м³
Вычислим: 
       $зt= \frac{10^7\cdot 2,1}{4200\cdot 1000\cdot 0,13}=38,46 \ кC$

Answer 2

Energy released from complete combustion of gas:

The energy released from the complete combustion of gas can be calculated using the calorific value of the gas. The calorific value is a measure of the energy content of a fuel and is typically expressed in units of energy per unit of mass or volume.

Unfortunately, the search results did not provide a specific calorific value for gas. The calorific value of gas can vary depending on the type of gas being burned. However, natural gas, which is commonly used for heating and cooking, has a calorific value of around 37 MJ/m³ (megajoules per cubic meter) [[1]].

To calculate the energy released from the complete combustion of 3 cubic decimeters (dm³) of gas, we need to convert the volume to cubic meters.

1 cubic meter (m³) = 1000 cubic decimeters (dm³)

Therefore, 3 dm³ of gas is equal to 0.003 m³ of gas.

Using the calorific value of natural gas (37 MJ/m³), we can calculate the energy released as follows:

Energy released = Calorific value * Volume of gas = 37 MJ/m³ * 0.003 m³ = 0.111 MJ

Therefore, approximately 0.111 megajoules of energy would be released from the complete combustion of 3 dm³ of gas.

Energy released from complete combustion of kerosene:

Similarly, the energy released from the complete combustion of kerosene can be calculated using the calorific value of kerosene. The calorific value of kerosene is approximately 43 MJ/kg (megajoules per kilogram) [[2]].

To calculate the energy released from the complete combustion of 3 dm³ of kerosene, we need to convert the volume to kilograms.

The density of kerosene is approximately 0.8 kg/dm³ [[3]].

Therefore, 3 dm³ of kerosene is equal to 2.4 kg of kerosene.

Using the calorific value of kerosene (43 MJ/kg), we can calculate the energy released as follows:

Energy released = Calorific value * Mass of kerosene = 43 MJ/kg * 2.4 kg = 103.2 MJ

Therefore, approximately 103.2 megajoules of energy would be released from the complete combustion of 3 dm³ of kerosene.

Heating water using dry firewood:

To calculate the temperature increase of water when burning dry firewood, we need to consider the heat capacity of water and the energy released from the combustion of dry firewood.

The specific heat capacity of water is approximately 4.18 J/g°C (joules per gram per degree Celsius) [[4]].

Given that we have 130 liters of water, we need to convert the volume to grams.

1 liter of water = 1000 grams

Therefore, 130 liters of water is equal to 130,000 grams of water.

The energy released from the combustion of 1 kg of dry firewood is approximately 16.7 MJ/kg (megajoules per kilogram) [[5]].

Using the mass of dry firewood burned (2.1 kg) and the energy released per kilogram, we can calculate the total energy released:

Energy released = Energy released per kilogram * Mass of dry firewood = 16.7 MJ/kg * 2.1 kg = 35.07 MJ

To calculate the temperature increase of water, we can use the formula:

Energy released = Mass of water * Specific heat capacity of water * Temperature increase

Rearranging the formula to solve for the temperature increase:

Temperature increase = Energy released / (Mass of water * Specific heat capacity of water) = 35.07 MJ / (130,000 g * 4.18 J/g°C) ≈ 0.064°C

Therefore, burning 2.1 kg of dry firewood would increase the temperature of 130 liters of water by approximately 0.064°C.

Please note that these calculations are approximate and may vary depending on the specific conditions and properties of the fuel and water.