Equilibrium Reaction Lab

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IBDP Chemistry IA: Equilibrium Reaction Lab
Introduction:
Reactions are based on collisions of particles, in which the particles must have sufficient energy. Some chemical reactions are reversible, and when the rate of the forward reaction equals the rate of the reverse reaction, the process has reached equilibrium. As it will appear to have stopped, as there is no overall change due to the rates being equal.
Through this lab, we will be investigating one factor that will affect the equilibrium constant. The chemical reaction to determine the equilibrium constant is;
〖Fe〗^3 +_((aq))+SCN-_((aq))⇌ 〖FeSCN〗^2 +_((aq))

And to calculate the equilibrium constant; K_c
K_c= ( [〖FeSCN〗^(2+)])/([〖Fe〗^(3+)] [〖SCN〗^-])
To obtain the value of K_c of this reaction, we need to know the concentrations of iron (III) and thiocyanate. When the two solutions are mixed together, wait for a period of time to ensure equilibrium. As equilibrium is reached, we can apply ‘ICE’ method to calculate the concentration of thiocyanatoiron (III), x.
K_c= ( x)/(([〖Fe〗^(3+) ]-x) ([〖SCN〗^- ]-x))
Out of the three substances, SCN- is colourless, while 〖Fe〗^(3+) is dull yellow in 0.5M of〖 HNO〗_3. So the dominant colour for this equilibrium would be thiocyanatoiron (III) in brownish red which absorbs blue light. And so by using Beer-Lambert’s law, we will be able to calculate x: x=A/(ε×l) From the equation above, A is absorbance of the solution in equilibrium, ε is the molar absurdity of the molecule and l is the cuvette width; the length of which light goes through the cuvette.

Extra information:
Beer-Lambert Law states the absorbance of light at a certain wavelength is directly proportional to the concentration of a solution. Which basically means the darker t...

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