Topic #5: Energy Changes Flashcards
1
Q
What are endo and exothermic reactions?
A
Endo- takes in heat, positive enthalpy change
Exo- gives out heat, negative enthalpy change
2
Q
Reaction profile features
A
Activation energy must be on
Curve
Final energy
Energy change
3
Q
Formula for energy change?
A
Bonds broken - bonds formed = energy change
In endothermic, more energy is taken in to break bonds than is given out making them, and vice versa
4
Q
What is a cell and a battery?
A
Cell- 2 metals in contact with electrolyte
Battery- 2 or more cells
5
Q
Non-rechargeable batteries stop when?
A
When the reactants have all been used up
6
Q
What are fuel cells?
A
Powered by oxidation of hydrogen to make water, only waste product is water
7
Q
What are the disadvantages of hydrogen fuel cells?
A
Explosive hydrogen Expensive to obtain Not environmentally freindly to obtain Needs storage tanks Volatile
