C5 - Energy Changes

Question 1

Equation of a hydrogen fuel cell

Answer 1

2H2 + O2—> 2H2O
And when they recombine:
2O2 + 4H(+) + 4e(-) —> 2H2O

Question 2

What are the two types of reaction

Answer 2

Endothermic
Exothermic

Question 3

An exothermic reaction is when

Answer 3

Energy is released into the surroundings

Question 4

What is an endothermic reaction

Answer 4

When energy is taken in from the surroundings

Question 5

If the potential energy of a substance increases the kinetic energy…

Answer 5

Decreases

Question 6

If the kinetic energy of a substance increases the potential energy…

Answer 6

Decreases

Question 7

Positives of hydrogen fuel cells

Answer 7

-Produces no greenhouse gases/polluting gases
-Renewable
-Very quick to refuel cars

Question 8

Cons of hydrogen fuel cells

Answer 8

-Explosive
-Hard to store
-Don’t have the infrastructure

Question 9

In a chemical cell, how do we make the largest voltage

Answer 9

When there is a big difference in reactivity of the metal electrodes

Question 10

What happens at the anode

Answer 10

Oxidation

Question 11

What happens at the cathode

Answer 11

Reduction

Question 12

What happens if we use two electrodes of the same metal in a chemical cell

Answer 12

No reaction, so no current

Question 13

How does a chemical cell work

Answer 13

A chemical reaction provides a flow of electrons