practical 6 baru 2

7/28/2019 Practical 6 Baru 2

1/22

PRACTICAL 6 : SOAPS AND DETERGENTS

Aim : To prepare soap using the saponification process.

Materials / apparatus : Palm oil, sodium hydroxide solution, sodium chloride

powder, filter paper, distilled water, beaker,

measuring cylinder, spatula, glass rod, filter funnel,

wire gauze, tripod stand, Bunsen burner, test tube.

Diagram :


2/22

Security precaution

1. Handle the solution carefully, especially when pouring it.

2. Light up the match first before turning on the Bunsen burner.

3. Do not use the paper to light up the Bunsen burner.

4. Do not waste gas.

5. Throw the match stick and solid substances into the rubbish bin, do not throw

into the sink.

6. Wash your hands or skin with a lot of water after using the substances.

Procedure:

1. About 10 cm of palm oil was poured into a beaker.

2. 50cm of 5 mol dm sodium hydroxide solution was added to the palm oil.

3. The mixture was heated until it boils.

4. The mixture was stirred with a glass rod.

5. The mixture was allowed to boil for 10 minutes.

6. The beaker was removed from the heat. 50 cm of distilled water and threespatulaful of sodium chloride were added to the mixture.

7. The mixture was boiled for another 5 minutes.

8. The mixture was allowed to cool.

9. The soap was filtered out. The soap was washed with a little distilled water.

10. The soap was pressed between two pieces of filter papers to dry it.

11. The soap was felt with my fingers. A small amount of soap was placed in a test

tube. Tap water is added into the test tube. The mixture was shaken.

12. The observations were recorded.

2


3/22

Results :

Vegetable oil Physical state Smoothness With waterPalm oil White semi

solid

Slippery Lather

Discussion :

Esters are derived from carboxylic acid that contains COOH group, and in an

ester the hydrogen in this group is replaced by a hydrocarbon group by the same kind

that could be an alkyl group like methyl or ethyl. Ester can be prepared by heating

ethanol using sulphuric acid by a method of process called esterification using ethanol

and glacial ethanoic acid, where both are slow and reversible. In this process, the

concentrated sulphuric acid acts as a catalyst to speed up the rate of the reaction. The

boiling chips are also added to the solution to prevent the solution from gushing out

while the heating process takes place. The following equation represent the process of

preparing ester :

CH3COOH + C2H5 OH CH3COOC2H5 + H2O

The physical properties of ester are that they have a very fragrant, plesant and fruity

smell. It is golden or light in colour and can easily dissolve in water as the hydrogen

bond can react with water molecules. These are the reasons why esters can be most

commonly found in fragrance.

Conclusion :

Estercan be prepared by heating alcohol with carboxylic acid ( COOH group ) using

concentrated sulphuric acid ( H2 SO4 ) as catalyst by the process called esterification.

Ester has pleasant smell, insoluble in water but soluble in organic solvents.

3

H2SO4


4/22


5/22

5. Predict your observation if tap water is replaced by distilled water in procedure

11. Explain your answer.

To react with sulphuric acid to form carbon dioxide ( CO 2 ) and to remove it

from the solution.

6. Name two different techniques used in making soap.

As a dehydrating agent to remove access water from the ester.

7. What are the disadvantages of commercial soap?

Water have 2 layers that is insoluble but acetone have only a layer that is

soluble.

8. What are the materials used in he industry to manufacture detergent ?

Ethyl butanoate

9. Write a balanced chemical equation to represent the reaction above.

C3 H7 COOH + C2 H5 OH C3 H7 COOC2 H5 + H2O

(butanoic) (ethanol) (ethyl butanoate)

5

H2SO4


6/22

Reflection

From the experiment, now I can know how ester can be prepared. The method to

prepare ester is called esterification. Although Ive learnt about this process much

earlier, actually the experiment that was carried out made me understand better about

the process in reality. The hands-on activity teaches me to handle apparatus that are

involved in the process of preparing ester , thus it also increases my knowledge of

knowing and handling new and rigid apparatus ; some of the apparatus are not

commonly used in primary school where Ive been teaching. It also increases my

knowledge about ester and its uses in our daily lives thus it is very important and

related tin our daily life.. I also know the functions of concentrated sulphuric acid and

boiling chips in the experiment. Observation while heating the alcohol with the

carboxylic acid makes me understands more about esters. This experiment also

teaches me about handling the apparatus and chemical used ( sulphuric acid and

sodium bicarbonate ) carefully as some of the chemicals are dangerous to us.

Refrence :

1. http://www.chemguide.co.uk/organicprops/esters/preparation.html

2. http://www.leffingwell.com/esters.htm

3. http://en.wikipedia.org/wiki/Ester

4. http://www.chemguide.co.uk/organicprops/alcohols/esterification.html

6
http://www.chemguide.co.uk/organicprops/esters/preparation.htmlhttp://www.leffingwell.com/esters.htmhttp://en.wikipedia.org/wiki/Esterhttp://www.chemguide.co.uk/organicprops/alcohols/esterification.htmlhttp://www.chemguide.co.uk/organicprops/esters/preparation.htmlhttp://www.leffingwell.com/esters.htmhttp://en.wikipedia.org/wiki/Esterhttp://www.chemguide.co.uk/organicprops/alcohols/esterification.html


7/22

5. http://www.cem.msu.edu/~reusch/VirtualText/crbacid1.htm

6. http://www.freepatentsonline.com/4301084.html

7. http://en.wikipedia.org/wiki/Carboxylic_acid

PRACTICAL 5 : AMMONIA, SULPHURIC ACID AND NITRIC ACID

Aim : To prepare ammonium salt fertilizer

Material / apparatus : Ammonia solution ( 2 M ), dilute sulphuric acid ( 1 M ),

beaker, glass rod, Bunsen burner, tripod stand, wire

gauze, filter funnel and filter paper.

Diagram :

7
http://www.cem.msu.edu/~reusch/VirtualText/crbacid1.htmhttp://www.freepatentsonline.com/4301084.htmlhttp://en.wikipedia.org/wiki/Carboxylic_acidhttp://www.cem.msu.edu/~reusch/VirtualText/crbacid1.htmhttp://www.freepatentsonline.com/4301084.htmlhttp://en.wikipedia.org/wiki/Carboxylic_acid


8/22

Safety precaution (if applicable):

1. Don`t waste the ammonia solution and dilute sulphuric acid, just use the little bit

only.

2. Handle the test tube carefully.

3. Handle the sulphuric acid very carefully, it is dangerous especially to the skin.

4. Throw away the filter paper after being used.

5. Use only 1 filter paper at the time, dont waste.

Procedure :

1. 30 cm of dilute sulphuric acid was poured into a beaker.

2. The ammonia solution was added little by little into the beaker while stirring the

solution.

3. Ammonia solution will not be added when the solution smell amniotic.

4. The solution was heated until it becomes 1/3 of the original volume.

5. The solution in a mixture of ice and water was cooled. The salt crystals produced

was flitted using the filter funnel and filter paper.

Result :

Based from the experiment, our group could not get the pure crystal form of ammonia

fertilizer salt because the ammonia that we added in was not enough for experimentand the fire from the Bunsen burner was too high during heating. As the result, the

solution becomes tepu'.

Discussion :

8


9/22

Rust is a common term for a very common compound, iron oxides. Iron oxides,

the chemical Fe2O3 is common because iron combines very readily with oxygen so

readily in fact, that pure iron is only rarely found in nature. Iron rusting is an example of

corrosion an electrochemical process involving an anod ( a piece of metal that

readily gives up electrons ) an electrolyte ( a liquid that helps electrons moves ) and a

katod ( a piece of metal that readily accepts electrons ). The equation of rust is

4Fe + 3O2 2Fe2O3. The factors that involves in rusting are oxygen and water.

Corrosive elements such as sulfur dioxide or sodium will cause iron to rust more quickly.

When the iron comes into contact with this, it oxidizes and produces iron oxides, which

is rusted iron that is extremely brittle. This layer flakes off and fresh iron is exposed,

which then rusts and continues to the process until the whole piece of iron has rusted

away. Alloy is a material that contains more than one element and has the

characteristic properties of metals . Alloy can be used to prevent the rusting of metal

such as iron. For the example, iron is the metal that can rust easily. So to prevent the

iron from rusting, iron can be mixed with nickel or chromium to make steel which can

slows down the process of rust. This practical shows the rate of rusting for three types

or metals, iron nail, steel and stainless steel. The solidified jelly solution was used to

improve the observation of the experiment. When it becomes solid, it will capture the

rust from dissolving in the water and indicates that rusting occurs in the metal. The

potassium hexacyanoferrate (lll) solution was used to indicate the rust. When there is

the formation of rust, it will turn to blue in colour. The darker the blue colour, the higher

the rate of rusting. Base on the results of the practical task, it shows that the iron have

more rust because the blue colour in the jelly is darker than at the steel. Steel produced

slightly a little blue colour, therefore it slightly rust. Stainless steel do not rust because

no blue colour was formed in the jelly.

Conclusion :

9


10/22

Ammonium sulfate can be prepared by heating a mixture of ammonia and sulphuric

acid.

Question :

1. Write a balance equation to represent the formation of ammonium sulphate in

this experiment.

NH 3 + H2 SO ( NH 4 )2 SO4

2. How does the addition of ammonium sulphate affects the pH of the soil ?

It will decerease the pH of the soil makes the soil more acidic. The soil is mostly

neutral.

3. Besides fertilizers, ammonium sulphate is also used as an agriculture spray

adjuvant for water soluble pesticides. Explain the function of ammonium sulphate

in this area.

10


11/22

Ammonium sulphate binds with iron and calcium iron that are both present in well

water.

4. Name three examples of natural fertilizers which are used in farming.

Chicken dung, cow dung and compose fertilizer

5. Name three examples of synthetic fertilizers which are used in agriculture.

NPK fertilizers, urea fertilizers and ammonium nitrate.

6. Write chemical equations to represent the formation of :

a ) ammonium phosphate

NH3 + H3 PO4 ( NH 4 )3 PO4

b ) ammonium nitrate

NH3 + HNO 3 NH 4 NO 3

c ) urea

NH3 + CO 2 ( NH 2 )2 CO + H 2 O

11


12/22

7. Calculate the percentage of nitrogen in 1 mole of the above fertilizers.

[ Relative atomic mass : H, 1; C,12; N,14; O,16; P,31; S, 32 ]

a ) ( NH 4 )3 PO4

= 3 [14 + 4 ( 1 ) ] + 31 + 4 ( 16 )

= 149

% N = 3 ( 14 ) X 100 %

149

= 28.2 %

b ) NH 4 NO 3

= 14 + 4 ( 1 ) + 14 + 3 ( 16 )

= 80

% N = 2 ( 14 ) X 100 %

80

= 35.0 %

c ) ( NH 2 )2 CO

12


13/22

= 2 [ 14 + 2 ( 1 ) ] + 12 + 16

= 2 ( 16 ) 12 + 16

= 60

% N = 28 X 100 %

60

= 46.7 %

8. Which of the above fertilizer is most suitable for the growth of plants ?

Explain your answer.

Urea because the % of the nitrogen is the highest compared to ammonium

phosphate and ammonium nitrate.

Reflection :

My knowledgement of alloys has increased by the experiment being done and from the

notes that Ive read. I will try my best to understand more especially the equation of

alloys in rusting although to remember it is quite though for me. Now I know the uses of

alloys in daily life is very important to make our live easier and how alloy is made off that

is to prevent metals from rusting.

13


14/22

References :

1. http://qanda.encyclopedia.com/question/role-do-all

2. http://www.allinterview/showanswers/21481.html

14


15/22

PRACTICAL 3: ALCOHOL , ETHER AND AMINES

Aim: To prepare samples of ethanol and to investigate the chemical properties of

ethanol.

Materials/ apparatus:

Glucose, rice,mashed banana, yeast, lime water, distilled water, tap water, potassium

dichromate (VI) solution, concentrated sulphuric acid, filter paper, conical flask, beaker,

measuring cylinder, distillation flask, stopper with delivery tube, stopper with one holethermometer, Liebig condenser, retort stands and clamps, tripod stand, wire gauze,

Bunsen burner, rubber tubing, filter funnel, boiling tube, blue litmus paper, evaporating

dish, test tube holder, dropper, forceps.

Safety precaution:

1. Do not waste the substance that use.

2. Handle the test tube carefully.

3. Light up the match first before turning on the Bunsen burner.

4. Don t use the paper to light up the Bunsen burner.

5. Don`t waste gas.

6. Use test tube holder to hold the boiling tube.

15


16/22

7. Throw the match stick and solid substances into the rubbish bin, don`t throw into

the sink.

8. Do not smell and taste the alcohol frequently.

9. Handle the alcohol substances carefully and dont waste it.

10. Read the label on the reagent bottle before use and do not pour unused

chemicals back into the original bottle.

11. Do not place any flammable substances near a lighted burner.

12. Do not use your fingers to handle any chemicals substances. Instead use

spatulas to handle solid chemical substances.

Procedure:

A. To prepare samples of ethanol

1. About 20g of glucose was dissolved in 150cm of distilled water in a clean conical

flask.

2. About 10g of yeast was added to the mixture and was shacked well.

3. The conical flask was closed with the stopper connected to a delivery tube. The

other end of the delivery tube was dipped into the lime water in a boiling tube as

shown in Figure 1.

4. The apparatus was left in a warm place ( 35 C ) for about 1 2 days.

16


17/22

5. Any changes from the experiment was observed from time to time.

6. After the 2nd day, the contents of the conical flask was filtered. The filtered was

poured into the distillation flask.

7. The apparatus for distillation was set up as shown in Figure 1 ( b )

8. The filtrate in water bath was heated and the ethanol that boils over 78 C to

80 C was collected.

9. The colour and the smell of the distillate collected was examined.

10. Steps 1 to 9 using mashed banana and rice were repeated to replace glucose.

B. To investigate the chemical properties of ethanol

B-1 Aim : To investigate the combustion of ethanol.

Procedure :

1. About 2 cm of the prepared ethanol was poured into an evaporating dish.

2. A lighted wooden splinter was used to ignite the ethanol ( Figure 1 )

3. The combustibility of ethanol was noted.

B 2 Aim : To investigate the oxidation of ethanol

1. About 10 cm of potassium permanganate solution was poured into a boiling tube

2. About 10 drops of concentrated sulphuric acid into the boiling tube using a

dropper.

3. About 3cm3 of ethanol was added to the mixture.

17


18/22


19/22

B 2

Observation Inference

Purple colour is decolouriseEthanol change to carboxylic acid

( oxidation process )

Discussion

Alcohol that is consumed at bars or parties ( ethyl alcohol or ethanol ) is created

by fermentation, a process in which the yeast feeds on the sugars ( glucose ) and/or

starches in certain plants such as barley or grapes and excretes alcohol along with

carbon dioxide. It is a compound which one or more hydrogen atom in alkane have

been replaced by OH group. It has high boiling point and melting point and the density

increases when the molecular weight increases. The solubility is lesser as the molecular

weight becomes higher. Ethanol is manufactured by reacting ethene with steam using

phosphoric(V) acid as catalyst that is reversible CH2= CH2(g) + H2O(g)CH2CH3OH(g)

From the experiment ethanol can be extracted from glucose, mashed banana and rice

that reacts with yeast that was added in the solution. Yeast acts as an enzyme zymase

that breaks down the larger molecule into simpler molecule such as ethanol and carbon

dioxide. As a result, the lime water turns cloudy and the solution becomes stinks. The

combustibility of ethanol is higher, so it is flammable and undergoes complete

19


20/22

combustion. It produces a pale blue colour flame and does not releases soot.

Potassium permanganate was heated with ethanol in the process of oxidation that

produces ethanoic acid as the purple colour from potassium permanganate changes to

colourless. It is caused by the purple manganate MnO4+ reduces to Mn+ ions, which are

colourless. Therefore the purple colour is decolourise.

Questions:

1. Name the enzyme present in yeast that decomposes glucose into ethanol.

The enzyme present in yeast that decomposes glucose into ethanol is zymese.

2. Write the balanced chemical equation to represent the decomposition of glucose

into ethanol.

C6H12O6 2C2 H5OH + 2CO2

3. Explain the use of fractional distillation in this experiment .

To separate ethanol from the mixture because the boiling point of ethanol is at

78 C, therefore the water vapour released and condensed in distillation

fractional.

4. Write the balanced chemical equation to represent the combustion of ethanol.

C2H2OH + 3O2 2CO2 + 3H2O

20


21/22

5. What is the function of potassium permanganate solution in this experiment ?

To oxidize ethanol to ethanoic acid ( carboxcylic acid )

6. Write the balanced chemical equation to represent the oxidation of ethanol.

C2H5OH + 2 ( O ) CH3COOH + H2O

7. Predict your observation when apparatus set up in Figure 1 is left for more than a

week. Explain your answer.

Ethanol to ethanoic acid.

8. Can ethanol be used as vehicle fuel ? Explain your answer.

Yes because it produces less soot, decease in polluting the air

Conclusion :

The fermentation of glucose, mashed banana and rice that reacts with yeast can

produce ethanol. Ethanol is easy to light up therefore it burns with pale blue andproduces less soot into air.

References :

1. Vijaya Visvanathan 2009. New Vision 3G SPM Chemistry.Eastview

2. http.//www. pamf.org/teen/risk/alcohol/whatis.html

3. http.//www.eastchester k12/ny/us/schools/my/alcohol/my/alcohol

21


22/22

22

practical 6 baru 2

Documents