Final answer:
To heat 250 mL of water from 20.0°C to 100.0°C to make a cup of tea, 83,680 joules (or 83.68 kilojoules) of energy are required, calculated using the specific heat capacity of water.
Step-by-step explanation:
To calculate the energy required to heat water to make a cup of tea, we use the formula q = mc∆T, where q is the energy in joules, m is the mass of the water in grams, c is the specific heat capacity of water (4.184 J/g°C), and ∆T is the temperature change. For 250 mL of water (which has a mass of approximately 250 grams, assuming a density of 1 g/mL), and a temperature increase from 20.0°C to 100.0°C (the boiling point of water at sea level), the calculation would be as follows:
q = (250 g) × (4.184 J/g°C) × (100.0°C - 20.0°C)
This results in:
q = 250 g × 4.184 J/g°C × 80.0°C
q = 83,680 J
Therefore, the energy required to heat 250 mL of water from 20.0°C to 100.0°C for making tea is 83,680 joules or 83.68 kilojoules (kJ).