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Chemical reaction - Coggle Diagram
Chemical reaction
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Thermic reactions
When a chemical reaction happens, energy is transferred to or from the surroundings. When energy is transferred to the surroundings, this is called an exothermic reaction, and the temperature of the surroundings increases. Examples of exothermic reactions include: combustion reactions, many oxidation reactions and most neutralisation reactions
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These are reactions that transfer energy to the surroundings (ie the energy exits from the reaction, hence the name exothermic). The energy is usually transferred as heat energy, causing the reaction mixture and its surroundings to become hotter. A thermometer is used to detect the temperature increase.
When energy is taken in from the surroundings, this is called an endothermic reaction and the temperature of the surroundings decreases. Examples of endothermic reactions include: thermal decomposition reactions, the reaction of citric acid and sodium hydrogen carbonate. Everyday uses of endothermic reactions include instant ice packs which can be used to treat sports injuries.
These are reactions that take in energy from the surroundings (ie energy enters the reaction, which will help you to remember the name endothermic). The energy is usually transferred as heat energy, causing the reaction mixture and its surroundings to become colder. A thermometer is used to detect the temperature decrease.
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Chemical equations
In a reaction, the substances you have at the start are called the reactants. The reactants' atoms are broken apart and then reconnected in a different order to make something new.The new substances are called the products.
There are two types of chemical equations: word equations and symbol equations. A chemical equation is always shown with the reactants on the left of an arrow and the products on the right.Reactants → products
If there is more than one reactant or product, then they are written with '+' signs between them.There can be any number of reactants or products - it all depends on the chemicals involved. It is important to remember that the little number in a formula tells you how many of each atom you have and that the little number goes on the right of an atom
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Enthalpy diagrams
An enthalpy diagram plots information about a chemical reaction such as the starting energy level, how much energy needs to be added to activate the reaction, and the ending energy. An enthalpy diagram is graphed with the enthalpy on the y-axis and the time, or reaction progress, on the x-axis.