If you are a meat eater, you are less likely to suffer from zinc deficiency as meats are one of the best foods rich in zinc. The meats that have the highest concentration of zinc include beef, lamb, pork, chicken and turkey. A 100 gram serving of cooked lean beef contains 12.3 mg or 82% DV of zinc.
Endothermic reactions absorb energy from the surroundings, while exothermic reactions release energy to the surroundings. Fuels release energy when they burn. The energy output of a fuel can be measured by calorimetry using a known mass of water.
Exothermic and endothermic reactions both cause some type of energy level differences. In an exothermic reaction, energy is released in the form of heat. As chemical bonds are formed, energy is released. An example is water turning into ice. Chemical bonds form and release energy to create ice crystals. An endothermic reaction, however, is the opposite. Here, the energy is absorbed in the form of heat. When a chemical bond is broken, the energy used creates an endothermic reaction. Changing ice into water, then vapor, requires the chemical bonds to be broken.