(Chapter 5) Energy Changes

Includes electrolysis (a feature of Chap. 4). There is a matching pair of A5 revision cards.

HideShow resource information
What is electrolysis?
The decomposition of ionic compounds using electricity.
1 of 16
Which ions are discharged at the anode?
Negative ions: Oxygen is produced frp, the discharge of hydroxide ions. unless the ionic compound contains halide ions, when a halogen is produced.
2 of 16
Which ions are discharged at the cathode?
Positive ions: Hydrogen is produced from the discharge of hydrogen ions, unless the compound has ions LESS reactive than hydrogens, as then that metal is at the cathode.
3 of 16
What are exothermic reactions? Endothermic reactions?
Reactioons that transfer heat to the surroundings, so the temperature increases. Endothermic reactions draw in heat, so temperature decreases.
4 of 16
What is activation energy? What is enthalpy?
The minimum energy particles must have to react. Enthalpy is the heat in a system in a reaction.
5 of 16
When do bonds need, or release bonds?
Breaking bonds needs energy. Making bonds releases energy.
6 of 16
What is the bond energy in an exothermic reaction?
Negative energy change as more energy is released than that energy that is needed.
7 of 16
What is the bond energy in an endothermic reaction?
Positive energy change as more energy is needed to break bonds than is released making new bonds.
8 of 16
How do you work out enthalpy change?
Substitute in the bond energies, then subtract the value on the left of the arrow FROM that on the right to work it out.
9 of 16
How do you calculate energy change?
Energy needed breaking bonds - energy needed making bonds.
10 of 16
How do lemon/potato batteries work?
The acid within the lemon reacts with the positive and negative electrode. When the reaction occires, electrons flow between the materials and an electric current in created.
11 of 16
What is a cell? A battery?
A cell is a single unit, a battery is a group of cells.
12 of 16
What is an electrolyte?
A liquid that conducts electricity
13 of 16
What is a fuel cell?
A chemical cell where the cells keep replacing those that are used up creating a continuous supply.
14 of 16
What happens inside a fuel cell?
At one electrode, hydrogen loses electrons and forms ions, they move to the other electrode, the electrons move to the other electrode through wire, the hydrogen ions and electrons react with the oxygen making water.
15 of 16
How does current flow between two metals?
As of the potential difference between them from the most to least reactive metal. The voltage us dependent in the difference between the metals (bigger difference, higher voltage) and the electrolyte.
16 of 16

Other cards in this set

Card 2

Front

Which ions are discharged at the anode?

Back

Negative ions: Oxygen is produced frp, the discharge of hydroxide ions. unless the ionic compound contains halide ions, when a halogen is produced.

Card 3

Front

Which ions are discharged at the cathode?

Back

Preview of the front of card 3

Card 4

Front

What are exothermic reactions? Endothermic reactions?

Back

Preview of the front of card 4

Card 5

Front

What is activation energy? What is enthalpy?

Back

Preview of the front of card 5
View more cards

Comments

No comments have yet been made

Similar Chemistry resources:

See all Chemistry resources »See all Energy of reactions/Exothermic and endothermic reactions resources »