Question

В водонагревательный котёл положили 7 кг деревянных дров и 5 кг торфа. Определи количество воды в водонагревательном котле, если его Кпд равен 85 %, а вода нагрелась на 50 градусов Цельсия. Удельная теплоёмкость воды равен 4200 Дж/(кг* К). Удельная теплота сгорания деревянных дров 12 МДж/кг и торфа 9 МДж/кг. В ответе запиши только число, округлённое до целых значений (в кг), без указания размерности. ПОМОГИТЕ ПОЖАЛУЙСТА, У МЕНЯ НЕ ПОЛУЧАЕТСЯ!!!!

Answer 1

$Q_1=nQ_2 \\ cm_{water}t=n(q_1m_1+q_2m_2) \\ m_{water}= \frac{n(q_1m_1+q_2m_2)}{ct} \\ m_{water}= \frac{0.85(12*10^6*7+9*10^6*5)}{4200*50} =522.2l$

Ответ: m_{water} = 522.2 л

Answer 2

Calculation of the Amount of Water in the Water Heater

To calculate the amount of water in the water heater, we need to consider the energy transferred from the burning of wood and peat to the water. We can use the following formula:

Q = m * c * ΔT

Where: - Q is the energy transferred to the water (in joules) - m is the mass of the water (in kilograms) - c is the specific heat capacity of water (in joules per kilogram per degree Celsius) - ΔT is the change in temperature of the water (in degrees Celsius)

First, let's calculate the energy transferred from the burning of wood and peat:

Energy from wood = mass of wood * specific heat of wood Energy from peat = mass of peat * specific heat of peat

Next, let's calculate the energy transferred to the water:

Energy transferred to water = Energy from wood + Energy from peat

Now, we can rearrange the formula to solve for the mass of water:

m = Q / (c * ΔT)

Given the following values: - Mass of wood = 7 kg - Mass of peat = 5 kg - Specific heat capacity of water = 4200 J/(kg*K) - Change in temperature of water = 50°C - Efficiency of the water heater = 85%

Let's calculate the mass of water in the water heater.

Energy from wood = 7 kg * 12 MJ/kg Energy from peat = 5 kg * 9 MJ/kg

Energy transferred to water = (Energy from wood + Energy from peat) * Efficiency

m = (Energy transferred to water) / (c * ΔT)

Now, let's substitute the values into the formula and calculate the mass of water.

m = ((7 kg * 12 MJ/kg) + (5 kg * 9 MJ/kg)) * 0.85 / (4200 J/(kg*K) * 50°C)

Calculating this expression, we find that the mass of water in the water heater is approximately 0.036 kg.

Please note that the calculation assumes that all the energy from burning the wood and peat is transferred to the water and that there are no other energy losses in the system.