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Exothermic and Endothermic Reactions In Everyday Life

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Lydia D'souza

on 6 November 2012

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Transcript of Exothermic and Endothermic Reactions In Everyday Life

BY: Aleena Pirzada, Hibah Sultan & Lydia D'souza Exothermic and Endothermic Reactions In Everyday Life Exothermic reactions involve the release of thermal energy as it flows out of the system, -(∆H), and results in less energy produced in the product is less than the initial amount of energy in the reactant. The reason for the negative ∆H produced is because the energy is being released, meaning there is less energy, but it is only being transferred to the surroundings. Endothermic Cellular Respiration A glucose molecule is broken down in cellular respiration to produce energy which is transferred through the body by ATP (Adenine Triphosphate). This happens in 4 Stages.
2)Pyruvate Oxidation
3)Krebs Cycle
4)Electron Transport Chain and Chemiosmosis
Only ¾ of these stages will produce energy in the form of ATP. Exothermic Cold Packs The cold pack is made up of 2 bags, an inner one and an outer one. The inner bag can be just water while the outer bag has ionic salts such as Ammonium Nitrate. When the pack is squeezed, the inner bag breaks and the ionic salts dissolve in the water. It takes heat from its surrounding for this reaction. The surrounding for the ice pack is the person. Hot Packs The hot pack is made up of 2 bags, an inner one and an outer one. The inner bag can be just water while the outer bag has ionic salts such as magnesium sulfate or calcium chloride. When these react with the water they give off heat. They are used to treat injuries as they promote the increase of blood to damaged areas. They are used for treating injuries and for warming hands and feet during cold weather. Uses: Uses Cold packs are used in injuries for shrinking bruises as they decrease the flow of blood. And it is also for chilling food and liquids. Sweat Water evaporating is a common form of endothermic reactions. The water takes the heat to turn from a liquid to a gas.
So the water in the sweat evaporates by taking the heat from the body, therefore cooling it down. Water Hvap = 40.67 kJ/mol Cooking The process of cooking food is endothermic as you have to give the food energy to have a chemical reaction.
For example :
Frying an egg is endothermic as the egg will absorb the energy of the pan and will therefore cook. Substrate-Level Phosphorylation and Oxidative Phosphorylation Through processes called Substrate-Level Phosphorylation and Oxidative Phosphorylation, both being exothermic reactions. Substrate level-oxidation forms ATP directly, in an enzyme catalyzed reaction. Oxidative Phosphorylation forms ATP indirectly, through a series of enzyme catalyzed redox reaction, using oxygen as the final electron acceptor. Glycolysis An endothermic reaction that effects the human body but does not involve it directly is photosynthesis. Photosynthesis is the opposite of cellular respiration. While cellular respiration is found in the human body, photosynthesis is not. Photosynthesis is instead found in plants, which we humans as omnivores consume on a regular basis. In this reaction energy in is absorbed from the sun, in order to take carbon dioxide and water and using the solar energy, convert it to glucose and oxygen to be used as food for the plant. PHOTOSYNTHESIS 1st and 2nd Law of ThermoDynamics Main distinction: Net Gain vs. Net Loss
Relation to Laws of Thermodynamics:

First Law of Thermodynamics: Energy cannot be created or destroyed, only transferred.
Second Law of Thermodynamics: All changes, directly or indirectly, increase change in entropy of the universe. Lightsticks or glowsticks are used by divers, campers, and for decoration and fun. A lightstick is a plastic tube with a glass vial inside it. To activate a lightstick, you bend the plastic stick, which breaks the glass vial. This allows the chemicals that are inside the glass to mix with the chemicals in the plastic tube. These two chemicals react and release energy. Another part of a lightstick is a fluorescent dye which changes this energy into light, causing the lightstick to glow! GLOW STICKS ADP + Pi ATP
- They contain a super saturated solution of water and sodium acetate (NaC2H4O2)
- Liquid at room temperature, snapping metal disk starts to crystallize
- Exothermic reaction taking places, so produces heat and solution changes to solid (hot ice!)
-The addition of a seed crystal starts the rapid crystallization
- Can be reused by melting crystals, (boil and allow to cool)
-Small crystals used to grow larger crystals of the same material are called seed crystals. Sodium Acetate Hand Warmers! Electron Transport Chain THANK YOU FOR LISTENING !! Combustion Reactions Combustions reaction of methane contributes to power and electricity.
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