To calculate the energy needed to heat water, we can use the formula:
Q = mcΔT
where:
- Q = heat energy (in Joules)
- m = mass of the water (in kg)
- c = specific heat capacity of water (approximately 4.18 J/g°C)
- ΔT = change in temperature (in °C)
Given that we have 200 ml of water, the mass of the water is 200 grams (since the density of water is about 1 g/ml). Assuming room temperature is around 20 degrees Celsius, and we want to heat it to 40 degrees Celsius, the change in temperature (ΔT) would be:
ΔT = 40°C – 20°C = 20°C
Now, substituting the values into the formula:
Q = (200 g) * (4.18 J/g°C) * (20°C)
Q = 200 * 4.18 * 20 = 16,720 Joules
So, the energy needed to heat 200 ml of water from room temperature to 40 degrees Celsius is approximately 16,720 Joules.