Question

сколько надо сжечь керосина чтобы нагреть 500 грамм воды от 20 до 100 градусов цельсия считая что на нагревания воды идёт 50% теплоты сгоревшего керосина?

Answer 1

КПД равен:

η=Qполезное/Qзатраченное *100%

Qполезное=cm₁(t2-t1)   - нагревание воды

Qзатраченное=qm₂        - сгорание топлива

η=cm₁(t2-t1)/qm₂

 

m₂=cm₁(t2-t1)qη        =4200*0.5*(100-20)/40,8·10⁶ *0.5 = 0.008235 кг.  или 8,235 грамм.

Answer 2

Calculation of the Amount of Kerosene Needed to Heat Water

To calculate the amount of kerosene needed to heat 500 grams of water from 20 to 100 degrees Celsius, we need to consider that 50% of the heat generated by burning the kerosene is used to heat the water.

First, let's calculate the heat required to raise the temperature of the water from 20 to 100 degrees Celsius. We can use the specific heat capacity of water, which is approximately 4.18 Joules per gram per degree Celsius.

The formula to calculate the heat required is:

Q = m * c * ΔT

Where: - Q is the heat required - m is the mass of the water (500 grams) - c is the specific heat capacity of water (4.18 J/g°C) - ΔT is the change in temperature (100 - 20 = 80 degrees Celsius)

Substituting the values into the formula:

Q = 500 g * 4.18 J/g°C * 80°C = 167,200 J

Since only 50% of the heat generated by burning the kerosene is used to heat the water, we need to divide the calculated heat by 0.