Lab Report IA help

[Sandy]

Hey! I've taken chemistry HL and my IA is about studying the effect the change in concentration of different electrolytes at cathode has on the emf of a voltaic cell. I've kept the electrode and electrolyte at anode constant and observed the change in emf for different concentration of (8 different) electrolyte and electrode combination at the cathode. The problem I'm facing is in the introduction. Can you give an example for purpose of this IA? Basically, why it is necessary to know the change in emf for different electrodes.

[kw0573]

So your topic is in the core HL topic. The following are hints on what you can talk about.

 

A formula is given on Table 1 of the chemistry data booklet that is directly related to your topic. Also on that table it relates a quantity from your lab to another important thermodynamic value. But this value is only given for standard conditions, how would non-standard concentrations in the cathode affect this other value? What's the significance of this value?

So in terms of physics (which obviously you know), what is emf? In an electrical circuit, what other (eg power, resistance, current etc) quantities are varied when you change emf? How may any of the these changes be significant?

 

[Siddhakshi]

I don't know much about physics but I do know a good application in bio of an electrochemical cell, that is the electrocardiograph. Here, two factors are most important: the emf developed must be optimum so that a) the patient is not harmed/ does not feel pain, and

b) measurements are not adversely influenced.

 

So here it is imperative that the emf falls within certain limits, and perhaps your IA aims to find the combination of electrode and electrolytic concentration which produces the most optimum emf. However, you have not mentioned the electrolyte you have used- chloride electrolytes are best for use in the body due to its large number of chloride ion receptors. You'd also need to research in depth the electrodes that are safe to use in the body. In other words, which of your experimented electrodes are best in terms of utility? Then you would have secondary sources in your IA as well, perhaps some good publications to support your conclusion. 

 

Your IA has 3 factors in question, so you'd have to research each one individually in terms of use in the body.

 

Just one example of many applications in biomed.

 

Hope this helps!