Chemisrty

Chemisrty

Aim:

To determine what combination of metal half-cells will give the best voltage and design a piratical to confirm this by making and testing at least 3 different combinations.

Equipment

  Several 100ml beakers
  Various salt solutions
  Various metal electrodes
  Electrical leads
  Voltmeter
  Filter Paper
  Solution for salt bridge
  Tweezers

Variables

Dependent:

The dependent variable in this experiment is the standard reduction potentials (voltage) obtained from the redox reaction produced from the two half-cells. The standard reduction potentials will vary due to   the effect of replacing the redox reactants with different half-cells

Independent:
The metal half-cells is the only component in this experiment that we would be changing in order to collect our results.

Controlled
The potassium nitrate (KNO3) salt bridge is kept the same but it is replace with a new one to prevent any sort of contamination during the experiment

Prediction
From looking at the standard reduction potentials (SRP) table and from my calculation I can be safe to assume the Magnesium (Mg) and the silver (Ag) redox reaction would have the best voltage.

Method

  Collect the different metal half-cells solutions the teacher already prepared.
  Place each metal electrode in its corresponding ionic solution; e.g. copper strip goes into the CuSO4 solution. It is important that the correct metal is in the correct solution or your cell will not work properly
  place some potassium nitrate (KNO3) into the Petri dish. Take a small strip of filter paper that has been soaked into the potassium nitrate solution and use the tweezers to roll it. This acts as the salt ridge. Use a fresh strip pf paper for each measurement in the procedure
  Carefully remove the completely wet strip and place one end in the CuSO4 solution and the other in the Zn(NO3)2solution. The salt bridge should not touch the electrodes.
  Attach one alligator clip from the...