C7 Flashcards
Define an exothermic reaction
A reaction which gives out energy into the surroundings
Define an endothermic reaction
A reaction that takes in energy from the surroundings
Define Activation energy
The minimum amount of energy needed to start a reaction
Define Bond energy
The amount of energy required to break a specific chemical bond
What is a fuel cell?
Sources of electricity that are supplied by an external source of fuel
What is an electrode
A positive or negative terminal which allows for the transfer of electrons during electrolysis
What is electrolysis?
The breakdown of a substance containing ions by electricity
What is an electrolyte solution?
A liquid which contains free moving ions, which are broke down by electricity in the process of elecrolysis
What type of reaction are displacement reactions?
And how does it vary in energy?
Exothermic reaction
Which releases more energy as the gap in reactivity series increases
What is the formula for calculating energy transfer?
Eq = M C T
Energy = mass X specific heat capacity X change in time
What is the oxidation equation at the anode of a hydrogen fuel cell?
2H2 = 4H+ + 2E-
What is the reduction equation at the cathode of a hydrogen fuel cell?
O2 + 4H+ + 4E- = 2H2O
What is the full equation for reactions in a hydrogen fuel cell
O2 + 2H2 = 2H2O
What are 2 advantages of a hydrogen fuel cell
- only produces H20
- No greenhouse gas produced (clean energy)
- lasts longer than a battery
What are 2 disadvantages of a hydrogen fuel cell?
- hydrogen is a gas which makes storage dangerous (explosions)
- required energy to store
-can be explosive when mixed with air
