3.2 Students' experiments.docx
------------------------------------------------------------------------------------------------------------Experiments for module „Carbon nature of life“:
A. Evidence of carbon, oxygen and hydrogen in paraffin
Tools and ingredients: beaker (min 250 ml), petri dish, limewater, paraffin candle (tealight), forceps
Procedure: Put burning tealight in the beaker. After a while cover the beaker with petri dish. When the tealight
douses watch sides of the beaker and put the tealight out . Pour limewater in the beaker and shake it. Take a
picture of the reaction.
B. Evidence of carbon in wood
Tools and ingredients: 2 test tubes, plug with hole, glass tubule, sawdust, limewater, stand, cotton-wool swab,
CuSO4 * 0,5 H2O
Procedure: Pour dry sawdust in the first test tube, close it with the plug with glass tubule.Build the aparature
according to the plan. Heat the mixture of solid substances and watch reaction in both test tubes . On the side of
the test tube with sawdust are drops of liquid. Wipe them carefuly with swab, that has been coated in anhydrous
solution of CuSO4 . Examine, describe or take a picture of the reactions.
C. Evidence of carbon in organic materials
Tools and ingredients: candle, sugar, flour, piece of plastic, forceps, porcelain shard , matches, 3 test tubes,
burner, test tube holder
Procedure: a) Grab the porcelain shard in the forceps and put it in the flame of the candle. When ye put the
shard from flame, examine its surface.
b) Pour separately sugar, flour, and piece of plastic (only if ye got digestar). Put the test tube in the flame and
heat it in the flame of burner. Examine the test tubes.
Working sheet – tasks for pupils
1.
Which element creates most advanced
solutions? Which branch of chemistry
studies these solutions?
Carbon creates most advanced solutions.
Apart from H2CO3, HCN, carbonates and cyanids they are
studied by organic chemistry.
2.
Are there natural reactions which creates
organic substances from anorganic?
Are there reverse reactions which creates
anorganic substances from organic
Which natural proces is responsible for the
things on the first picture
Yes, for example fotosynthesis – water and carbon dioxide
are amended into glucosis and oxygen
Yes, for example decay of corpses, or burning of organic
materials.
Charring
How long takes this proces in nature?
How looked the saucepan from the short
story „Yesterday...” like? To what color the
milk changed? What was the reason for this
change?
What elemen caused the processes written
above?
Thousands of years
The saucepan was dark brown. This was caused by singe
of the milk. Carbon in the milk was reduced into
elemental form.
8
Can we take these processes as a evidence
of the carbon in organic materials
Yes, carbon couldn’t be created from nothing, it was part
of solutions from which it has been separated
9
Acording to the cards prove that there is
3
4
5
6
7
Carbon, C
carbon, oxygen and hydrogen in organic
materials
Work sheet – instructions and tasks for pupils
Experiment
A
Ingredients:
Tools:
Examination:
1. Describe what happened in the beaker after ye covered
it.
2. describe how limewater looked after it was poured into
the beaker .
3. What was the substance that caused the change?
Conclusion:
The reaction proved presence of certain elements in
paraffin. Which elements are those?
Experiment
B
Ingredients:
Tools:
Plan of the aparature:
Examination:
1. Describe what solid substances were heated.
2. Describe chages in the test tubes with limewater. Which
substance was proved by these changes?
3. Describe how anhydrous CuSO4 loked before and after
the experiment.
4. What did the reaction proved?
Experiment
C
Conclusion:
The reaction proved presence of certain elements in dry
wood. Which elements are those?
Ingredients:
Tools:
Examination:
1. How did the porcelain changed after heating?
2. What did the color of porcelain proved?
3. Describe how the test tubes looked like before and after
reaction .
4. What element was proved by the reaction?
1 The tealight slowly ceased to
burn There were little drops on the
side of the beaker and some smoke
within it. .
2. In the limewater there was white
turbidity at he bottom
3. The turbidity is evidence of
carbon dioxide.
Presence of oxygen and carbon
was proved in paraffin.
1.The sawdust was dry and without
bark.
2. The limewater blurred. The
escaping glasss was carbon
dioxide.
3. Anhydrous CuSO4 was greyish
blue after contact with drops on the
sides of the beaker it was blue.
4. the reaction proved that drops
are from water
The experiment proved that there is
hydrogen, moxygen and carbon in
the wood.
1. Před pokusem byl porcelán bílý,
po pokusu černý.
2. Černá barva je důkazem C.
3. Jednotlivé materiály měnily
původní bílou nebo světlou barvu
na hnědou až černou.
4. Hnědá až černá barva je
důkazem C.
Conclusions:
The experiment proved presence of one element in organic
materals, which one?
Carbon
Final
conclusions
What elements were proven by performed experiments?
Which branch of chemistry studies materials like wood,
flour, wax, plastic etc. ?
Carbon, hydrogen and oxygen
were proved. These materials are
studied by organic chemistry