Final answer:
The energy needed to raise or lower the temperature of 1 g of liquid water by 1 degree Celsius is 4.184 J/g °C, which is also equivalent to 1 calorie (cal). This measure is known as the specific heat of water.
Step-by-step explanation:
The amount of energy that must be absorbed to raise or lower the temperature of 1 g of liquid water by 1 degree Celsius is known as the specific heat of water. The specific heat of water is 4.184 J/g °C, which means that to raise the temperature of 1 g of water by 1 °C would require 4.184 Joules of energy. It's important to note that the specific heat value pertains to the amount of energy needed to change the temperature of a given mass of a substance by a certain temperature interval.
In other contexts, this amount of energy is referred to as 1 calory (cal), which is the amount of heat needed to raise the temperature of 1 g of water by 1 °C. Therefore, whether we express the energy in calories or Joules, the principle remains the same: the heat energy required to raise the temperature of water is directly proportional to the mass and the change in temperature.