Question

At home cooks need to boil 1 liter of water on the stove. What temperature does water boil at?

1) 0°C
2) 50°C
3) 100°C
4) 150°C

Answer 1

Water boils at a temperature of 100°C under standard atmospheric conditions. It would require approximately 80 kcal, or 334,720 Joules, to heat 1 liter of water from room temperature (20°C) to boiling point. The correct option is 3.

Step-by-step explanation:

The temperature at which water boils is 100°C (at standard atmospheric pressure). This means that to boil 1 liter of water on the stove, the water needs to reach this temperature. The process of boiling involves heating the water until it reaches this temperature and starts to change from the liquid to the gaseous phase.

To calculate the energy needed to heat 1 liter of water from room temperature (20°C) to its boiling point, you would need to know the specific heat capacity of water, which is approximately 1 kcal/kg°C (or 4.184 kJ/kg°C). The energy in kilocalories (kcal) can be found by multiplying the mass of the water, the change in temperature, and the specific heat capacity.

For a 1 liter (1 kg) sample of water, this would be 1 kg × (100°C - 20°C) × 1 kcal/kg°C = 80 kcal. To convert this to Joules, you would use the conversion factor of 1 kcal = 4184 Joules, giving a result of 80 × 4184 J = 334,720 Joules.