# Required Practical...help

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#1
Production of a dilution series of a glucose
solution and use of colorimetric techniques to produce a calibration
curve with which to identify the concentration of glucose in an
unknown ‘urine’ sample.

I have drawn the calibration curve and got the values for my glucose conc samples. What am i to do with these values?

Why did we have to use a Colorimeter? why red light?
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3 years ago
#2
Think you need to plot the urine sample from your question against the graph you just drew, it should give you some information about the urine absorbtion or transmission figure and then you put that on your graph go up to the curve you drew then go along to give you a concentration figure for the urine sample.
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#3
(Original post by Setekh)
Think you need to plot the urine sample from your question against the graph you just drew, it should give you some information about the urine absorbtion or transmission figure and then you put that on your graph go up to the curve you drew then go along to give you a concentration figure for the urine sample.
Yes, i did all that but what do i do with these values, I obtained for the concentration

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....also if you could tell me, why we had to use a colorimeter?
why red light.....

0
3 years ago
#4
That figure is the answer to your question it is the concentration of glucose in your unknown urine sample so you don't need to do anything with it it's just the answer to your practical question.

A colorimeter is used because you can work out an unknown glucose concentration by comparing concentrations of serial dilutions against it on a graph. A colorimeter works because the more concentrated a sample is of glucose it will absorb more light and it will transmit less by using this you can figure out glucose concentrations. A red filter is used because the filter you use has to be the opposite colour (in a colour wheel) to the colour of your sample. You added Benedict's solution into your glucose samples and that is blue/cyan in colour and so a red colour is required. For example if your solution was a pinkish colour you would use a green filter.
1
#5
(Original post by Setekh)
That figure is the answer to your question it is the concentration of glucose in your unknown urine sample so you don't need to do anything with it it's just the answer to your practical question.

A colorimeter is used because you can work out an unknown glucose concentration by comparing concentrations of serial dilutions against it on a graph. A colorimeter works because the more concentrated a sample is of glucose it will absorb more light and it will transmit less by using this you can figure out glucose concentrations. A red filter is used because the filter you use has to be the opposite colour (in a colour wheel) to the colour of your sample. You added Benedict's solution into your glucose samples and that is blue/cyan in colour and so a red colour is required. For example if your solution was a pinkish colour you would use a green filter.
Thank you so much. Love you
1
#6
(Original post by Setekh)
That figure is the answer to your question it is the concentration of glucose in your unknown urine sample so you don't need to do anything with it it's just the answer to your practical question.

A colorimeter is used because you can work out an unknown glucose concentration by comparing concentrations of serial dilutions against it on a graph. A colorimeter works because the more concentrated a sample is of glucose it will absorb more light and it will transmit less by using this you can figure out glucose concentrations. A red filter is used because the filter you use has to be the opposite colour (in a colour wheel) to the colour of your sample. You added Benedict's solution into your glucose samples and that is blue/cyan in colour and so a red colour is required. For example if your solution was a pinkish colour you would use a green filter.
I thought the more concentrated a sample is of glucose, when benedict is added it should decolourise shouldn't it?, when this happens the sample is no longer blue..............
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