CHEM,PLEASE HELP ME!

1.
I guess that iodine solution (in the conical flask) is titrated against sodium thiosulphate solution (in the burette). The following data should be used :
Volume of iodine solution used = viodine cm3 (say, 10 cm3)
Concentration of iodine solution = Miodine mol dm-3
Volume of thiosulphate solution used = vthiosulphate cm3

Equation :
I2(aq) + 2S2O32-(aq) → 2I-(aq) + S4O62-(aq)

Calculation steps :
No. of moles of S2O32- = Mthiosulphate x (vthiosulphate/1000) = a mol
Mole ratio I2 : S2O32- = 1 : 2
No. of moles of I2 = a / 2 = b mol
Concentration of I2 = b / (viodine / 1000) = c mol dm-3

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2.
The answer depends on what the reaction is.

For example, consider the following reaction :
I2(aq) + CH3COCH3(aq) → CH3COCH2I(aq) + H+(aq) + I-(aq)
(H+(aq) ions act as the catalyst of the reaction.)
Rate = k [CH3COCH3] [H+]
Since the reaction is zeroth order with respect to I2, the rate of reaction is independent of the concentration of I2.

For other reactions :
If the reaction is first order with respect to I2, the rate of reaction is directly proportional to [I2].
If the reaction is second order with respect to I2, the rate of reaction is directly proportional to [I2]2.

if the concentration of thiosulphate is unknown, i just found the volume of thiosulphate used to titrate iodine solution, how can i find out the concentration of thiosulphate?

concentration (molarity) = no. of mole of substance / volume in dm3
so, you may first calculate the no. of mole of sodium thiosulphate by mole ratio in chemical equation.
then, you can do the calculation using the formula above.

sorry, i don't know what your graph is about
i mean, the x- and y-axis