Activity 8: Flocculation - starch


During this class we performed 5 experiments:
Firts of all, at the beginning of the class, the teacher showed us a box where we could see the 5 experiments on the right side and above there were letters (A, B, C, D and E). Once we have the results of the experiments, we have to fill out the boxes inside

Soluble in water
Lugol test
Fehling test


The aim of the study in the firts experiment is to identify the 5 types of sugars that were presented to us and then relate it to each letter.
We don’t need materials for this experiments, but we use 5 types of sugar: lactose, glucose, starch, maltose and sacarose.
To carry out this experiment, simply we try the 5 types of sugars to identify them correctly.
The conclusions we extracted them quickly and correctly. And they are the following; A (lactose) B (glucose) C (starch) D (maltose) and E (sacarose).

Lugol test: It is soluble in water?

The aim the study in this experiment, is to know 2 things; in one hand we want to know which sugars are soluble in water and which ones do not, on the other hand we want to know which sugar it has strach.

The materials that we use are: 5 test tubes, test tube rack, spatula, pipet, a baker and a pickles.
And the subtance that we use are: 2ml of destilled water, small amounts of each sugar (lactose, glucose, starch, maltose and sacarose) and some drops of lugol.

Firts of all we mark each test tube with a letter, as it is easier to identify where each sugar is found. Secondarily we take 10ml of distilled water and spoil 2ml in each test tube, so we take the pipette that helps us to take the precise amount. Then, I have to attach a small amount off sugar, as I said before, each tube has its letter, so that acoording to the letter that marked it, we put a type of sugar or another, for example, if the letter A is in the tube, it will mean that lactose is the sugar you strip it. Then we wait a few minutes to see if something happens, then we can see how the test tube of the letter A that corresponds to the lactose, is not soluble in water and the other solutions if they are. With this we can already finish the second experiment, but we need a part of the third experiment. Next we pull a few drops of lugol in each test tube. Finally we note that the solutions are yellow, except the A, that means that it contains strach.
The conclusions that we extract in this experiment are that the lactose are not soluble in water and contains strach.


Fehling test

The aim of this experiment is to identify which substance are positive in glucose and which not.
The material that we use for realise this experiment are: 5 test tubes, pickles, baker, tripod, thermometer, pipete, spatula, grid, and fire.
The substance that we use are: Fehling susbtance, 2ml of distille water, types of sugar (lactose, glucose, maltose, strach and sacarose).
The methodology for realise this experimemt consist in take 5 test tube, which the same letters than the previous experiment. And firts of all we have to put 2ml of distilled water in each test tube, then we put a small amount of sugar corresponding to each letter and then put some drops of fehling substance. Next we have to shake because that way everything will be mixed. One time are mixed we prepare the “bany maria” to do it we need a tripod from which we put to upper part a grid, under the tripod and place for fire, which will warm the baker where the test tube will be extracted. Then inside the baker we put the thermometer to know the temperature in wich the water is located and until it reaches 80 degrees we will not have it. So that arrives in this temperature we have to wait for a while minutes. Of which we can see that the test tube C, D, A turn yellow and the test tube B and E do not react.
The conclusions for this experiment are that the test tube that turns yellow that are C, D, A are positives ans the tubes B and E that don’t react are negatives but we did wrong the experiment because it was had to turn blue and it doesn’t work.
Anothere thing, is that it cost to carry out this experiment since we were wrong when it came to throwing the reagent fehling and thats what it doesn’t affect.



Activity 8: Flocculation - starch Activity 8: Flocculation - starch Reviewed by Elisabet Mas de les Valls on November 22, 2018 Rating: 5

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