Results
Aspirin Type
Fake
Run
Measurement
1
2
3
4 (if needed)
Mass of Powder (g)

0.6g
0.5g
0.5g

Volume of NaOH added (ml) = Y
9ml
9ml
9.5ml

Moles of NaOH added to flask (mol) = Y x 0.1 1000
0.0009
0.0009
0.00095

Moles of aspirin which reacted with NaOH (mol) = Z
(1:1 reaction so Z is the same as the number of moles of NaOH added to flask – above calculation).
0.0009
0.0009
0.00095

Mass of aspirin which reacted with NaOH (g) = Z x Mass of 1 mole of aspirin (180.2g)

0.16218
0.16218
0.17119

% aspirin in tablet calculated by titration = Formula 1 (on previous page)

32%
32%
34%

Average = 32.6%

Type Aspirin
Length Travelled
Rf Values
A E110
6.8cm
6.8/7= 0.9714285714
B E124
6.5cm
6.5/7= 0.92857143
C E127
5.3cm
5.3/7= 0.75714286
D1 Warehouse
6.5cm
6.5/7= 0.9517
D2 Warehouse
5cm
5/7= 0.714283571

The warehouse said they had a new colour when actually it is just a mixture of E110 and E127.

Why are RF values important?
RF values are important as it helps us compare and unknown substance and be able to analyses it. It also helps us work out the difference between different substances as they all literally have their own substance. It also allows us to identify them with other substances once we have our results as it will we already know the values for them. So we mostly use it to determine unknown samples.

Melting Point for Aspirins
Run
Pure Aspirin (°C)
Impure Aspirin (°C)
1
136
148
2
137
149
3
138
150
Average
137
149

Based on the titration we have found that the impure sample has 43.25% of aspirin compared to the pure aspirin that had 88% we can also back our evidence up as the melting point of the impure sample was 149 whereas the pure sample was 137.

Describe the reasons why a sample of aspirin may not be 100% pure and why the method of sampling is so important in influencing the overall result.
One of the reasons why the sample may not be fully pure is because there still could be other substances left on the equipment, which would mean it mixes with the aspirin so therefore it wouldn’t be fully pure, this could be something like the spatula