Question

Which one of the following is required calories of heat to increase temperature by 10º C for 1 gram of water?
1. 1 calorie
2. 10 calories
3. 32 calories
4. 5 calories

Answer 1

Correct Answer - Option 2 : 10 calories

The concept of Calory:

• Calorie, abbr. cal, a unit of heat energy in the metric system.
• The measurement of heat is called calorimetry.
• The calorie, or gram calorie, is the quantity of heat required to raise the temperature of 1 gram of pure water 1°C.
• The kilocalorie, or kilogram calorie, is the quantity of heat required to raise the temperature of 1 kg of pure water 1°C; it is equal to 1,000 cal.
• The kilocalorie is used in dietetics for stating the heat content of a food, i.e., the amount of heat energy that the food can yield as it passes through the body; in this context, the kilocalorie is usually called simply the calorie.
• The amount of heat energy needed to effect a 1°C temperature increase in 1 gram of water varies with temperature (see heat capacity); thus the temperature range over which the heating takes place must be stated to define the calorie precisely.
• The 15° calorie, or normal calorie, is widely used in chemistry and physics; it is measured by heating a 1-gram water sample from 14.5°C to 15.5°C at 1-atmosphere pressure.
• The 4° calorie, also called the small calorie or therm, is measured from 3.5°C to 4.5°C (water is most dense at 3.98°C); the large calorie, or Calorie, is equivalent to 1,000 small calories.
• The average value of the calorie in the range 0°C to 100°C is called the mean calorie; it is  1⁄100 of the energy needed to heat 1 gram of water from its melting point to its boiling point.
• The calorie may also be defined by expressing its value in some other energy units.

Hence, 10 calories is required calories of heat to increase the temperature by 10º C for 1 gram of water