Energy from Bonds Flashcards
0
Q
What happens in an endothermic reaction?
A
More energy is needed in the product bonds and the extra energy is taken from the surroundings, making the temperature fall.
1
Q
What happens in an exothermic reaction?
A
Less energy is needed in the product bonds than the reactant bonds, the spare energy is released as heat.
2
Q
What are the advantages of hydrogen fuel?
A
It is not a fossil fuel
It does not give off Co2 or Sulphur dioxide emissions
Stores three times as much energy per kg than petrol
Used in a fuel cell is 60% efficient
3
Q
What are the disadvantages in hydrogen fuel?
A
Electrolysis is expensive and needs electricity
Can only be stored as a compressed gas
Much larger fuel tank
Only 20% efficient in a car
