Chemistry experiment english

Experiment 5

Hydrolysis catalysed by Saliva

How to work:

First boil the starch and water mix in a beaker above the burner. Then fill a boiling tube with the starch mix. Get 5 test tubes with 4 drops of iodine and 5 other test tubes with 6 drops of benedict’s solution. Put 4 drops of the starch mix into 1 est tube of iodine and 4 drops into the benedict’s solution. Now wait and see what happens…

After this, fill a large beaker with water and heat it up to 40° over a burner. Then put the boiling tube of starch mix into the beaker. Then add saliva to the starch mix. Test this mix with the iodine and benedict’s solution. Use a pipette to drop 4 drops into each test tube. repeat this test with each test tube, at few minute intervals.

Observations:

1.There was no reaction with the Benedict’s solution, except boiling. With the iodine, the colour changed slightly to indigo.

2. Minutes later, with the starch/spit/benedict’s solution mix, there was still no reaction:

The Iodine went a darker blue:

3. The benedict’s solution wenta slightly darker blue/ slightly darker blue/ slightly green:

The iodione went a dark black.

4. The benedict’s solutiob went a turquiose green:

The iodion went indigo:

5. The benedict’s solution went a green turquiose colour:

The iodine, a darker indigo:

Conclusion: This experiment shows the beginning stages of digestion. The amylose in our saliva turns the starch into sugar.

Experiment 6

Fermentation:is the process in which a substance breaks down into a simpler substance. Microörganisms like yeast and bacteria usually play a role in the fermentation-process, creating, for example : beer, wine, bread, yogurt and other foods.

What you need:

-beaker

-burner

-thermometer

-banana

-yeast

How to work:

Fill the beaker up to 600 ml with water. Put it above the burner till its up to 36° . Put some mushed up banana in the water and some yeast as well.

Put it in two flasks with stuppers on it, with also two rubber hoses, which meet each other again in a bin from glass.

Observations:

The banana sinks and most of the yeast sinks as well. Some yeast floats in the water. The water turnes murky/cloud /white/yellow. After a while some bubbles arise. Slowly there arises a yeast foam on top of the water. You can smell the banana and the yeast very well. Some of the bananary stuff rises as well after a while.

Then put it in the two flasks

After a day there arise little bubbles on the yeast, which contain carbondioxide. In the bin is now a transparant liquid, which looks like water.

Conclusion: Yeast and sugar reacting in a waterly environment release carbondioxide and there is ethanol alcohol being produced.

Alcohol and water disolve into each other. This is called a liquid liquid solution.

This process is also called fractional destilation.

In this case we can assume there is a little bit of alcohol produced.

Immiscible: liquids don’t dissolve into each other.

miscible: liquids disolve into each other and form a liquid liquid solution.

Experiment 8

Steam distillation of an orange

How to work:

Set up the apparatus as shown above⇑. Then cut the orange in small pieces and boil it above the burner -100°.

Observations:

Condensation forms into the conical flask and in the delivery tube. Then the vapour passes in the condenser before it condenses.

Conclusion:

The essential oil is was ectracted from the orange, in the form of oil/orange juice condensate.

Extracting essential oil from Condensate

How to work:

PUt the condensate into the seperating funnel, the condensation vessel still had a really strong smell. After all the watery liquid dripped through, there was ony a little bit of oil left.

Conclusion:

The small bit of oil left gave a very very strong smell, showing that the little amount still gave a strong smell.

Experiment 9

Separating alcohol from fruit juice by fractional distillation.

How to work:

Set up what’s shown above ⇑. Boil up the wine up to -78°.

Observations:

The steam from the ethanol went up the fractionating column and then through the liebig condenser where it turned into condensate, collecting in the condensate vessel.

Conclusion:

Fractional Distillation seperates miscible liquids.