Chemical Reaction Temperature Changes
The capacity of a system to do work or the quantity required for mechanical work to take place. Measured in joules (J). For example, a man transfers 100 J of energy when moving a wheelbarrow. is transferred to or from the surroundings when a chemical reaction happens. This often causes changes in How warm or cold something is. that can be measured using a An instrument used to measure temperature..
Reactions can be Reaction in which energy is given out to the surroundings. The surroundings then have more energy than they started with so the temperature increases. or Reaction in which energy is taken in.. The table shows some differences.
| Exothermic | Endothermic | |
| Energy | Given out | Taken in |
| Temperature | Increases | Decreases |
| Examples | Combustion, acid-alkali neutralisation | Electrolysis, thermal decomposition |
| Energy | |
|---|---|
| Exothermic | Given out |
| Endothermic | Taken in |
| Temperature | |
|---|---|
| Exothermic | Increases |
| Endothermic | Decreases |
| Examples | |
|---|---|
| Exothermic | Combustion, acid-alkali neutralisation |
| Endothermic | Electrolysis, thermal decomposition |
The slideshow describes an exothermic reaction between dilute sodium hydroxide and hydrochloric acid, and an endothermic reaction between sodium carbonate and ethanoic acid.
Image caption, Sodium hydroxide solution is poured into a beaker of hydrochloric acid which contains a thermometer showing room temperature
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In endothermic reactions, energy enters. In exothermic reactions, energy exits.
A study of the energy changes involved in chemical reactions, whether exothermic or endothermic