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.
In a molecule or compound, a majority of the energy is held in the bonds that link the molecules. Bonds have varying strengths. When a reaction occurs that causes these bonds to break, it gives off energy and is, therefore, exothermic. Examples of Exothermic Reactions. Exothermic reactions are very common. Let's take our match example from the beginning. The friction that is caused when you rake the matchhead against a rough surface ignites the phosphorus and potassium chlorate in the head of the match and they continue to burn with the oxygen in the air.