I was wondering if anyone would be able to check my method for my Chemistry Internal Assessment on the Rate of hydrolysis of Aspirin.
Independent variable (I am changing): temperature (degrees celsius)
Dependent variable (I am finding): time (seconds)
Method
1. Measure out 100 cm3 of the pH 7.5 buffer solution into a conical flask. Put this on a magnetic stirrer/electric hotplate and bring the temperature up to 70 °C.
2. Add 0.10 g of powdered aspirin to the buffer solution and stir the mixture gently until the aspirin is completely dissolved. No measurements should be made until all the solid has dissolved.
3. Pipette 5 cm3 of iron(III) nitrate reagent directly into a colorimeter tube. Pipette 1 cm3 from the reaction mixture and empty it into the colorimeter tube. Mix well and measure the absorbance. The intensity of the colour and, therefore, the absorbance value depends on the concentration of the hydrolysis product 2-hydroxybenzoic acid.
4. Take 1 cm3 samples every 15 minutes for at least 2 hours and treat them as in step 4.
5. Use the calibration graph produced in Determination of 2-hydroxybenzoic acid to calculate the concentration of 2-hydroxybenzoic acid in solution at each time interval. If it is wrong could you please help me correct it and give me some insight into how the hydrolysis of aspirin works, and how to measure the rate of it whilst changing the temperature.
Could someone check my method to see if it would work to find the rate of the reaction.
It would also help to know if I change the temperature in step 1 at different temperatures to find different results. Also I am unsure about step 4 in this method, like how does it work and why does it need to be 15. mins for 2 hours. Also what does it mean by 1cm3 samples
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Topic: Rate of hydrolysis of aspirin (Read 3369 times)