SXR103 - Day 5

I didn't get a lot of sleep last night, what with the very loud line dancing going on across the road (some kind of event) until gone midnight and the recycling truck picking up the glass at 6 am. So the alarm going off was not a welcome sound.

Still we are doing chemistry today so I'm in a good mood, so after breakfast we all congregate sound the chemistry lab on the 4th floor of Chichester. The smell of a chemistry lab is so unique and it instantly brings back memories from 18 years ago. I'm really looking forward to this!!

After a quick safety briefing from our activity tutor (Danny) task 1 was some qualitative observations on the reactions between certain metal nitrates and several common lab reagents. This was a nice introduction with some pretty coloured compounds made.

 Next we had to identify which metal nitrate is in an unknown sample. For this we used the data previously gathered and come up with the correct answer, all very satisfying.

Now we moved onto quantitative analysis. We wanted to know how much aluminium is in a sample of water to determine whether it meets recommended levels. For this we use a commercial test kit which includes a colorimeter. The catch is that each group wil test a different concentration of the solution so we can plot a graph and arrive at a constant of proportionality which can be used to convert the figure from the colorimeter to the value of the concentration. I found this experiment nice and easy (which you would expect from a commercial kit) and we came up with a pretty good figure (according to Danny). However after getting the data from the others and plotting it the line of best fit was very loosely applied. Still we got a value, which at level 1 is the object.

Then there was just time for lunch, a very good chicken curry before we moved onto flame tests.

The activity tutors were a bit nervous about this part of the day, I'm not sure what had happened on previous days but we did fine and no one got burned. Basically we burnt a small sample of a metal chloride in a Bunsen flame and watched the pretty colours. We then used a hand-held spectroscope to look at the light being emitted by the burning salt, which was quite tricky to do and wasn't particularly satisfactory.

This had all been building up the main event of the afternoon, using the grating spectrometer. This fiddly bit of kit allows you to measure the angle of diffraction for a particular element being excited either through combustion or electrification. We started getting to know this tool by looking at the spectra of a sodium vapour lamp. From this we managed to calculate the spacing of the lines on the diffraction grating in nanometres. This was quite a mind-blowing thing. Here we are looking at glowing lines through a small telescope and after taking a few readings we can get a figure that small!

The final task of the day was to look at the spectra of a metal salt being blown through a flame and identify the metal involved. I found this fiendishly difficult and only managed to identify my metal by discounting the others but some of the other groups had their "eye in" and were going great guns.

The lab was over and as this was our last practical of the week (tomorrow we get to do a research poster) I have to say that I'm going to miss the labs. They were really well written and led you naturally through to a conclusion.

I decided not to do any optional tutorials or lectures, I was tired and needed to sort my notes out for the day.
Not really looking forward to tomorrow but the end is in sight.