A kilogram...1,000 grammes...2.2lbs
2.7 kilos. The prefix "kilo" (symbol k) in the International System of Units (SI) and other systems, which denotes 103, it means one thousand. Therefore, there are 1,000 grams (g) in a kilogram (kg) and 0.001 kilogram equal a gram. Kilograms and grams are units of mass not volume such as liters, gallons, quarts, pints, and cups, and can only be conveted to each other if you have the specific item being measured, as each item has a different density.
Thermal energy is measured in calories. All substances have a property called the specific heat capacity, which means the number of calories it takes to heat 1 gram or 1 Kgram of the substance by 1 degC. (If you use Kg instead of g, you get kilocalories).