C3.2 - Energetics Flashcards
what kind of reaction is it if the temperature of the surroundings increase?
exothermic
state three examples of an exothermic reaction
- combustion
- neutralisation
- oxidisation
what kind of reaction is it if the temperature of the surroundings decrease?
enodothermic
state 2 examples of endothermic reactions
- photosynthesis
- thermal decomposition
what happens during a chemical reaction?
- bonds break in the reactants to produce separate atoms
- new bonds form between atoms to make products
what is the energy transferred during reactions measured in?
kilojoules (kJ)
what is a reaction profile?
a chart that shows the energy involved in a reaction
What is activation energy
minimum energy needed for a reaction to start
why do acids and alkalis react without heating?
the activation energy is so low, that the reactants already have enough energy
what happens in an endothermic reaction?
the amount of energy transferred to break bonds is more than the energy transferred when bonds are formed
if the energy change is ‘234kJ’, then what energy change is this?
endothermic
if the energy change is ‘-283’ then what kind of energy change is this?
exothermic
What happens during an exothermic reaction?
the amount of energy transferred to break bonds is less than the energy transferred when bonds are formed
what is a bond energy? (2)
energy required to break 1 mole (1) of a particular bond (1)
what is bond energy measured in?
kJ/mol
