C11 - Energy Changes (PAPER 1) Flashcards
What is an exothermic energy transfer
energy is transferred from the reaction to the surroundings
What is an endothermic energy transfer
energy is transferred from the surroundings to the reaction
What is a reaction profile
a diagram showing the energy changes in a reaction
What is the activation energy
minimum amount of energy required before a collision will result in a reaction
What is bond energy
the energy required to break a bond or the energy released when a bond is broken
are breaking as bond and making a bond endothermic or exothermic
making bonds release energy
breaking bonds requires energy
In terms of bond making and breaking, what is an exothermic reaction
less energy is required to break the bonds than is released making the bonds
In terms of bond making and breaking, what is an endothermic reaction
more energy is required to break the bonds than is released making the bonds
How are chemical cells made
connecting two different metals (electrodes) in a solution (electrolyte
What are examples of exothermic and endothermic reactions
endothermic - thermal decomposition, citric acid and sodium hydrogen carbonate
exothermic - combustion, oxidation, neutralisation,
What is a battery
two or more chemical cells connected in series
How does the potential difference of a cell depend on the metals that the electrodes are made of
The bigger the difference in reactivity, the greater the potential difference
Why can some cells not be recharged
the reaction cannot be reversed
How can some cells be recharged
by applying an external current
What is a fuel cell
cell that uses a fuel and oxygen to generate electricity
