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StylishNugget
1 year ago

Chemical reactions are processes in which chemical compounds are converted. Energy plays an important role. The activation energy is the energy needed to start a chemical reaction. It is, to some extent, the “hurdle” which must be overcome so that the reaction can take place.

  • Endothermic reactions are chemical reactions in which energy is absorbed from the environment. This means that the reaction requires energy to run. A known example is photosynthesis in which plants use light energy to convert carbon dioxide and water into glucose.
  • Exothermic reactions are, on the other hand, chemical reactions in which energy is emitted to the environment. This releases energy. An example of this is the combustion in which, for example, wood reacts in the presence of oxygen with the release of heat energy.
Avoc33
1 year ago

enthalpy H is the energy in chemical reactions. DeltaH: Endotherm = Energy is released (usually in the form of heat, e.g. burn of wood), DeltaH is NEGATIV. Endotherm = the reaction absorbs energy from the environment, it cools down (e.g. wash soda + citric acid), DeltaH is POSITIV.

In order for a chemical reaction to take place, a little energy has to be put in, the activation energy E_a (for example, a candle does not ignite at room temperature by itself, with a lighter (supplies activation energy) is only released).

If temperature T and entropy (unorder, chaos) S are still observed, the Gibbs enthalpy G is obtained. If DeltaG is NEGATIV, a reaction is exergon/spontane, at DeltaG it is positive endergon/enforcement.

ADFischer
1 year ago
  1. Exotherm: The car rolls down a hill.
  2. Endotherm: The car does not voluntarily roll up a hill, you have to push it.
  3. Activation energy: As 1., in between is a small peak, over which you have to push the car first.