Chemical Reaction l

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Balancing Reaction

Videos on How to Balance Reactions

Steps To Balance Equations Write Down Number of Atoms Add Coefficients To Balance Mass in a Chemical Equation Balance Oxygen and Hydrogen Atoms Last For any chemical equation (in a closed system) the mass of the reactants must be equal to the mass of the products.

Types of Reactions

Single-Replacement reactions: A more active metal displaces a less active metal in a compound A + BX = B + AX Double-Replacement reactions: A partner-swapping reaction AX + BY = BX + AY Decomposition reactions:A reaction to break down things A = B+ C Take 1 reactant and make many products Combustion Reaction: To combine things Take many reactants and make 1 product A + B = C

Endothermic vs. Exothermic Reactions

Videos On the Differences

https://www.youtube.com/watch?v=eJXL0IrbtqE

Endothermic- Require heat for the reaction occur In an exothermic reaction, the total energy of the products is less than the total energy of the reactants. Therefore, the change in enthalpy is negative, and heat is released to the surroundings 1) Photosynthesis: Plants absorb heat energy from sunlight to convert carbon dioxide and water into glucose and oxygen. 2)Cooking an egg: Heat energy is absorbed from the pan to cook the egg Exothermic - Repels heat Endothermic reactions are reactions that require external energy, usually in the form of heat, for the reaction to proceed. Since endothermic reactions draw in heat from their surroundings, they tend to cause their environments to cool down. They are also generally non-spontaneous, since endothermic reactions yield products that are higher in energy than the reactants Example of Exothermic =Combustion: The burning of carbon-containing compounds uses oxygen, from air, and produces carbon dioxide, water, and lots of heat. Rain: Condensation of water vapor into rain releasing energy in the form of heat is an example of an exothermic process.