Question

Физика 8 класс. Сколько надо сжечь каменного угля, чтобы нагреть 2л воды от 0С до кипения (100С). Записана дословно.

Answer 1

По формуле найдём Q нагрева воды
Q=c•m•(100-0)=840000Дж
найдём массу угля через формулу сгорания
Q=q•m
вырожаем массу
m=Q:q
m=840000:27000000
m=31 г-масса угля

Answer 2

Calculating the Energy Required to Heat Water

To calculate the energy required to heat 2 liters of water from 0°C to 100°C, we can use the formula:

Q = mcΔT

Where: - Q = the energy required (in joules) - m = mass of the water (in grams) - c = specific heat capacity of water (in J/g°C) - ΔT = change in temperature (in °C)

Specific Heat Capacity of Water

The specific heat capacity of water is approximately 4.18 J/g°C.

Mass of Water

The mass of 2 liters of water can be calculated using the density of water, which is approximately 1 g/cm³. Therefore, the mass of 2 liters (2000 cm³) of water is 2000 grams.

Change in Temperature

The change in temperature is from 0°C to 100°C, so ΔT = 100°C.

Calculation

Using the formula Q = mcΔT, we can calculate the energy required:

Q = 2000g × 4.18 J/g°C × 100°C

Q ≈ 836,000 J

Therefore, approximately 836,000 joules of energy are required to heat 2 liters of water from 0°C to 100°C.

I hope this helps! If you have any further questions, feel free to ask.