Energy changes Flashcards
What is an exothermic energy transfer
Transfer to the surroundings
What is an endothermic energy transfer
Transfer from the surroundings
What is a reaction profile
Shows energy changes over the reaction to tell whether a reaction is exothermic or endothermic
What is activation energy
Minimum amount of energy that particles must have to react when colliding
Is breaking bonds exothermic or endothermic and why
Exothermic
Less energy is required to break the bonds than is required to make the bonds
Is making bonds exothermic or endothermic and why
Endothermic
More energy is required to break the bonds than is released when making the bonds
What is the equation for bond calculations
Overall energy transfers = energy required to break bonds - energy required to make bonds
What are examples of exothermic reactions
Oxidation
Combustion neutralisation
What are examples of endothermic reactions
Thermal decomposition
What happens to the temp of the surroundings for exothermic reactions
Temp of surrounding increases
Energy is being released
What happens to the temp of the surroundings for endothermic reactions
Temp of surrounding decreases
Energy is being taken in
How are chemical cells made
Connect two different metals (electrodes) in a solution (electrolyte)
What is a battery
Two or more chemical cells connected in a series
How does the potential difference of a cell depend on the metals that the electrode is made of
The bigger the difference in reactivity the greater the potential difference
How can some cells be recharged
By applying an external current
