Question

На древесном угле массой 20г нагревают воду Взяли 200г воды и нагрели от 15° С до 55°C Найти КПД тепловой установки..

Answer 1

Ответ:

25 %

Объяснение:

1)

количество теплоты, необходимое на нагревание воды:

q₁ = m·c·(t₂-t₁)= 0,180·4200·(80-20) = 45 360

2)

сгорело спирта:

m₂ = 163-157 = 6 г   или   6·10⁻³ кг

выделилось количество теплоты:

q₂ = q·m₂ = 30·10⁶·6·10⁻³ = 180 000 дж

здесь q - теплота сгорания топлива.

3)

кпд тепловой установки:

кпд = q₁·100% / q₂ = 45 360·100% / 180 000 ≈ 25%

Answer 2

Calculation of Heat Energy

To find the efficiency (КПД) of a thermal installation, we need to calculate the heat energy supplied to the water and the heat energy absorbed by the water.

The heat energy supplied to the water can be calculated using the formula:

Q1 = m1 * c1 * ΔT1

Where: - Q1 is the heat energy supplied to the water - m1 is the mass of the water (200g) - c1 is the specific heat capacity of water (4.18 J/g°C) - ΔT1 is the change in temperature of the water (55°C - 15°C)

Substituting the values into the formula, we get:

Q1 = 200g * 4.18 J/g°C * (55°C - 15°C)

Calculating the above expression gives us the value of Q1.

The heat energy absorbed by the water can be calculated using the formula:

Q2 = m2 * c2 * ΔT2

Where: - Q2 is the heat energy absorbed by the water - m2 is the mass of the water (200g) - c2 is the specific heat capacity of water (4.18 J/g°C) - ΔT2 is the change in temperature of the water (55°C - 15°C)

Substituting the values into the formula, we get:

Q2 = 200g * 4.18 J/g°C * (55°C - 15°C)

Calculating the above expression gives us the value of Q2.

Calculation of Efficiency (КПД)

The efficiency (КПД) of a thermal installation can be calculated using the formula:

КПД = (Q2 / Q1) * 100%

Where: - КПД is the efficiency of the thermal installation - Q2 is the heat energy absorbed by the water - Q1 is the heat energy supplied to the water

Substituting the values of Q2 and Q1 into the formula, we can calculate the efficiency (КПД) of the thermal installation.

Calculation Example

Let's calculate the efficiency (КПД) of the thermal installation using the given values:

- Mass of the water (m1) = 200g - Specific heat capacity of water (c1) = 4.18 J/g°C - Change in temperature of the water (ΔT1) = 55°C - 15°C = 40°C

Using the formulas mentioned above, we can calculate the heat energy supplied to the water (Q1) and the heat energy absorbed by the water (Q2). Then, we can calculate the efficiency (КПД) of the thermal installation.

Please note that the specific heat capacity of water (c1) is approximately 4.18 J/g°C.

Let me calculate the values for you.