Final answer:
To find the amount of heat in calories to heat 2 kg of water from 20°C to 80°C, use the formula q = m × c × ΔT. The calculation gives you 120,000 calories, which is the energy required for heating the water to the desired temperature.
Step-by-step explanation:
To calculate the heat in calories required to heat 2 kg of water from 20°C to 80°C, you can use the formula for heat energy, which is q = m × c × ΔT, where q is the heat energy in calories, m is the mass of the water in grams, c is the specific heat capacity of water, and ΔT is the change in temperature.
Firstly, we need to convert the mass of water from kilograms to grams because the specific heat capacity of water is typically given in units of J/g°C and we want calories. Remembering that 1 kg of water is equivalent to 1000 grams, we have 2 kg of water which is 2000 grams. Also, the specific heat capacity of water is approximately 1 cal/g°C.
Next, we calculate the change in temperature (ΔT) by subtracting the initial temperature from the final temperature. So ΔT = 80°C - 20°C = 60°C.
Now, we can plug these values into our formula: q = 2000 g × 1 cal/g°C × 60°C.
Thus, q = 120,000 calories. Therefore, it would take 120,000 calories to heat 2 kg of water from 20°C to 80°C.