Saturday, 28 February 2015

6.2 Elektrolisis Sebatian Lebur

Proses elektrolisis
■ Elektrolisis

Proses penguraian elektrolit oleh arus elektrik ke dalam komponennya.
■ Sel elektrolisis

Sejenis sel yang menggunakan tenaga elektrik untuk menghasilkan tindak balas kimia.

Animasi berikut menunjukkan struktur asas sel elektrolisis.
■ Video berikut mengandungi maklumat tentang elektrolisis bagi sebatian lebur.

Aktiviti Makmal 6.2.1 : Elektrolisis sebatian lebur
Meramalkan hasil elektrolisis bagi sebatian lebur
■ Elektrolisis bagi leburan elektrolit,  AxBy 

Sebatian logam terbentuk di katod.

Bukan logam terbentuk di anod.

Secara umum, elektrolisis elektrolit lebur boleh diringkaskan seperti yang ditunjukkan dalam jadual berikut:
Garam dalam keadaan lebur Di anod  (+) Di katod (-)
Pergerakan ion ke elektrod Bx- Ay+
Setengah persamaan Bx- → B + xe- Ay++ ye- → A

Setengah persamaan menunjukkan apa yang berlaku di salah satu elektrod semasa elektrolisis.
Contoh 6.2(a)
Ramalkan hasil elektrolisis bagi leburan natrium klorida di anod dan di katod.

Penyelesaian
Garam dalam keadaan lebur Di anod (+) Di katod (-)
Pergerakan ion ke elektrod Cl- Na+
Setengah persamaan 2Cl- → Cl2 + 2e- Na++ e- → Na
Pemerhatian Gas kuning kehijauan Logam kelabu terbentuk
Hasil Gas klorin Logam natrium

Contoh  6.2(b)
Ramalkan hasil elektrolisis bagi leburan magnesium oksida di anod dan di katod.

Penyelesaian
Garam dalam keadaan lebur Di anod (+) Di katod (-)
Pergerakan ion ke elektrod O2- Mg2+
Setengah persamaan 2O2- → O2 + 4e- Mg2++ 2e- → Mg
Pemerhatian Gas tidak berwarna terbebas Logam kelabu terbentuk
Hasil Gas oxygen Logam magnesium


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Aktiviti Makmal 6.1.1 : Elektrolit and bukan elektrolit


Aktiviti Makmal 6.1.1 : Elektrolit and bukan elektrolit
 Tujuan: Untuk membezakan elektrolit dan bukan elektrolit bagi keadaan leburan dan larutan akueus.

Bahan:
»Plumbum (II) bromida
»Serbuk plumbum
»Kalium iodida
»Naftalena 

Apparatus:
»Bateri
»Mentol
»Elektrod karbon
»Penunu Bunsen
»Tugu kaki tiga
»Kasa dawai
»Mangkuk pijar
Prosedur

(A) Keadaan leburan
1. Animasi berikut menunjukkan prosedur dan pemerhatian eksperimen.
2. Mangkuk pijar diisi sehingga separuh penuh dengan serbuk plumbum (II) bromida.
3. Suis dihidupkan dan mentol direkodkan jika ia menyala.
4. Serbuk plumbum (II) bromida dipanaskan sehingga cair. Suis dihidupkan semula untuk memeriksa sama ada mentol menyala.
5. Eksperimen diulangi dengan menggunakan kalium iodida, serbuk plumbum, glukosa dan naftalena.

(B) Keadaan akueus
1. Animasi berikut menunjukkan prosedur dan pemerhatian eksperimen.
2. 2 – 3 spatula hablur kalium iodida ditambah ke dalam bikar yang mengandungi 250cm³ air.
3. Larutan dikacau sehingga kalium iodida terlarut.
4. Suis dihidupkan dan mentol direkodkan jika ia menyala.
5. Eksperimen diulangi dengan menggunakan glukosa.
Perbincangan:

(A) Keadaan leburan
Plumbum (II) bromida dan kalium iodida boleh mengalirkan elektrik dalam keadaan lebur kerana mereka mempunyai ion bercas yang bebas bergerak. Oleh itu, mereka adalah elektrolit.
Plumbum adalah konduktor yang baik.
Glukosa dan naftalena terdiri daripada molekul kovalen neutral. Tiada ion yang membawa cas elektrik wujug. Oleh itu, mereka bukan elektrolit.

(B) Keadaan akueus
Plumbum (II) bromida dan naftalena tidak larut dalam air. Oleh itu, ia tidak sesuai untuk digunakan dalam penyiasatan pengaliran elektrik dalam larutan akueus.
Larutan kalium iodida mengkonduksikan arus elektrik kerana ia mengandungi ion yang bergerak bebas dalam larutan.
Larutan glukosa terdiri daripada molekul. Tiada ion yang membawa cas elektrik wujud. Oleh itu, ia tidak boleh mengalirkan elektrik.
 Kesimpulan:

Elektrolit boleh mengalirkan elektrik di dalam keadaan leburan atau larutan akueus.


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Friday, 27 February 2015

6.1 Sifat Elektrolit dan Bukan Elektrolit

Sifat Elektrolit dan Bukan elektrolit
■ Elektrolit

Suatu sebatian yang hanya mengkonduksikan elektrik apabila dalam keadaan leburan atau larut dalam air(akueus).

Mengandungi ion yang bergerak bebas untuk membawa cas elektrik.

Mengalami penguraian kepada unsur-unsur apabila arus elektrik mengalir melaluinya.

Contoh :
Oksida dan hidroksida logam dalam keadaan leburan atau larutan berakueus(jika tidak larut).
Larutan akueus bagi asid mineral.
■ Bukan elektrolit

Satu sebatian yang tidak mengalirkan elektrik, sama ada dalam keadaan pepejal, leburan atau larutan akueus.

Tiada ion yang boleh membawa cas elektrik.

Tiada perubahan apabila arus elektrik mengalir melaluinya.

Contoh: Semua sebatian kovalen seperti naftalena, gula, benzena dan lain-lain lagi.
■ Video berikut memberi pengenalan ringkas kepada elektrokimia.



Aktiviti Makmal 6.1.1 : Elektrolit and bukan elektrolit


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Thursday, 26 February 2015

8.2.2 - Laboratory Activity : Qualitative analysis of salts


Laboratory Activity 8.2.2:
Qualitative analysis of salts
Aim: To confirm the presence of Mg2+ and NO- ions in a salt sample, X

Material:
» Magnesium nitrate powder
» FeSO4 solution
» Dilute sulphuric acid
» Concentrate sulphuric acid
» Sodium hydroxide solution
» Ammonia solution

Apparatus:
» Test tube
» Test tube holder
» Bunsen burner
Procedure:

(A) Heat test
1. A spatula of compound is heated in a test tube, slowly at first and then strongly.
2. The observation and inferences made are recorded.
Experiment Observation Inference
(a) the colour of gases released
(b) the effect on damp litmus
(c) the effect on glowing splint

(B) Brown ring test
1. Add water to compound X to make solution.
2. Add 2cm3 of dilute sulphuric acid and iron(II) sulphate, FeSO4 solution to the solution.
3. Concentrated sulphuric acid is then added slowly along the wall of the tilted test tube to the mixture without shaking.

(C) Compound X is dissolved in distilled water. The solution is divided into 2 portion.
1. Sodium hydroxide solution is added to the first portion of solution X until in excess.
2. Aqueous ammonia is added to the second portion of solution until in excess.
Results:

(A) Heat test
A spatula of compound is heated in a test tube, slowly at first and then strongly. The observation and inferences made are recorded.
Experiment Observation Inference
(a) the colour of gases released Brown gas. NO2 released.
(b) the effect on damp litmus Blue litmus turned red. Acidic gas released.
(c) the effect on glowing splint Rekindles glowing splint O2 released.
Probably NO3- present.

(B) Brown ring test.
Brown ring formed at the middle section of the solution mixture in the test tube, nitrate ion present.

(C) Compound X is dissolved in distilled water.
Experiment Observation Inference
(a) Add with NaOH White precipitate, insoluble in excess NaOH May be Ca2+ or Mg2+
(b) Add with aqueous ammonia White precipitate, insoluble in excess NaOH May be Pb2+, Al3+ or Mg2+
Probably NO3- present.
Conclusion:

The ions present in salt X are confirmed as Mg2+ and NO3- ions


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8.2.1 - Laboratory Activity : Test for anions


Laboratory Activity 8.2.1:
Test for anion
Aim: To test for carbonates, nitrates, chlorides and sulphates

Material:
» Sodium carbonate
» Sodium nitrate
» Sodium chloride
» Sodium sulphate
» Zinc carbonate
» Zinc nitrate
» Zinc chloride
» Zinc sulphate
» Copper carbonate
» Copper nitrate
» Copper chloride
» Copper sulphate

Apparatus:
» Test tubes
» Test tube rack
» Test tube holder
» Wooden splint
» Litmus paper
» Bunsen holder
Procedure:

(A) Colour and solubility in water
1. The colour of each salt is observed
2. 10cm3 water is added in test tube. The mixture is shakes and its solubility is observed

(B) Effect of heat
1. The salts are heated separately and the gas/gases which evolved are tested.

(C) Effect of dilute acid
1. Dilute hydrochloric acid is added to the salts.
2. The gas is passed into limewater.

(D) Confirmatory test for anions in solution
i. Confirmatory test for nitrates ion.
1. Dilute H2SO4 and FeSO4 is added to NaNO3 and mixed.
2. Then, a few drops of concentrated H2SO4 is added slowly along the test tube side.
3. These steps are repeated with Zn(NO3)2 and Cu(CO3)2.
ii. Confirmatory test for chloride ion.
1. Dilute HNO3 is added to NaCl solution, followed by silver nitrate solution.
2. Some Pb(NO3)2 solution is added to NaCl solution.
3. These steps are repeated with ZnCl2 and CuCl2.
iii. Confirmatory test for sulphate ion.
1. Dilute HCl is added to Na2SO4 solution followed by PbCl2 solution.
2. Pb(NO3)2 solution is added to Na2SO4 solution.
3. These steps are repeated with ZnSO4 and CuSO4 solutions.
Result:

(A) Colour and solubility in water
Salt In water Colour of salt
Na2CO3, ZnCO3, CuCO3 All salts are soluble except ZnCO3 and CuCO3. All salts are white except CuCO3 (green).
NaNO3, Zn(NO3)2, Cu(NO3)2 All salts are soluble All salts are white except Cu(NO3)2 (blue) .
NaCl, ZnCl2, CuCl2 All salts are soluble All salts are white except CuCl2 (blue).
Na2SO4, ZnSO4, CuSO4 All salts are soluble All salts are white except CuSO4 (blue).

(B) Effect of heat
Salt Observation Inference
Na2CO3 Does not decompose
ZnCO3 Gas released turns limewater chalky. Residue is yellow when hot, white when cooled. Blue litmus turns red. Carbon dioxide released. CO32- and Zn2+ ions present
CuCO3 Gas released turns limewater chalky. Residue is black. Blue litmus turns red. Carbon dioxide released. CO32- and Cu2+ ions present
NaNO3 Gas released rekindles glowing splint. Oxygen released
Zn(NO3)2 Brown gas released, Glowing splint rekindled. Residue is yellow when hot, white when cold. Blue litmus turns red. NO2 and O2 released. NO3- and Zn2+ ions present
CU(NO3)2 Brown gas released, Glowing splint rekindled. Brown residue. Blue litmus turns red. NO2 and O2 released. NO3- and Cu2+ ions present

(C) Effect of dilute acid
Salt Observation Inference
Na2CO3, ZnCO3, CuCO3 Effervescence seen. Colourless gas produced turns limewater chalky. CO2 gas released. CO32- ion is confirmed to be present.

(D) Confirmatory test for anions in solution
Salt Observation Inference
(i) Confirmatory test for nitrates ion. A brown ring is formed. NO3- ion is confirmed to be present.
(ii) Confirmatory test for chloride ion. A white precipitate is formed. White precipitate which dissolves when heated, then forms back when cooled is formed. Cl- ion is confirmed to be present. PbCl2 which is insoluble in cold water is formed.
(iii) Confirmatory test for sulphate ion. A white precipitate is formed. White precipitate insoluble in nitric acid. SO4- ion is confirmed to be present.
Discussion:

All Na+, K+, NH4+ nitrates salts are soluble in water.
All chlorides are soluble except for AgCl, HgCl and PbCl2.
All sulphates are soluble except for PbSO4, BaSO4 and CaSO4.
All carbonates are insoluble except for Na2CO3 and K2CO3.

The blue or green salts and solutions indicate the presence of Cu2+ ions.
All carbonates except Na2CO3 and K2CO3 release CO2 when heated.
All carbonates release CO2 when a dilute acid is added, confirming the presence of carbonate ions.

All nitrates except NaNO3 and KNO3 release NO2 and O2 when heated. NaNO3 and KNO3 release only O2 when heated
All nitrates from a brown ring when concentrated H2SO4 is added to a mixture of nitrate, dilute H2SO4 and FeSO4 solution.

All chlorides form a white precipitate with dilute HNO3 and AgNO3 solution. With Pb(NO3)2, a white precipitate soluble in hot water is formed.

All sulphates form a white precipitate with dilute HCl and BaCl2 solution. They also form a white precipitate with Pb(NO3)2 solution.
Conclusion:

Anions can be tested by
observing the colour and solubility of salts
observing the effect of heat on salts
performing confirmatory tests for specific anions


⇲ For exercise(objective and subjective), download for free on Android OS.

8.2 Qualitative analysis of salts

Qualitative analysis of salts
■ Qualitative analysis

A series of tests conducted on a chemical substance to identify the unknown component or components in it.

Can determine the cation and anion present.
■ This video contains information on the qualitative analysis of salt .
■ Technique of qualitative analysis.

Colour of salt

Solubility of salt in water

The effect of heat on the salt

Flame test and gas test

Identifying the precipitate formed with a specific chemical reagent

Confirmatory tests for ions


Colour of salt
■ Colour of salt

All cations are not coloured except copper(II) ions, [blue], iron (II) ion [green], iron (III) ion [yellow or brown].

None of the anions are coloured.

Colour Solid state Aqueous state
Colourless None Salts for Ca2+, Mg2+, Al3+, Pb2+, NH+4
White Salts for Ca2+, Mg2+, Al3+, Pb2+, NH+4 None
Black CuO, CuS, PbS, FeS None
Brown Fe3+, PbO Salt for Fe3+
Green Fe2+, CuCO3, CuCl2 Fe2+, Cu2+
Blue Salt for Cu2+ Salt for Cu2+
Yellow PbO, PbI2, PbCrO4, BaCrO4 Fe3+, CrO2-4


Solubility of salt in water
■ Solubility of salt in water

Solubility in water enable inferences to be formed on the type of cation and anion that may be present in the salt.

Salt Solubility in water
Na+, K+, NH+4 All are soluble
Nitrates All are soluble
Chlorides All are soluble except AgCl, HgCl and PbCl2 (soluble in hot water)
Sulphates All are soluble except BaSO4, PbSO4 and CaSO4
Carbonates All are soluble except Na2CO3, K2CO3 and (NH4)2CO3
Oxides All are soluble except Na2O, K2O and CaO
Hydroxides All are soluble except NaOH, KOH, Ca(OH2) and Ba(OH2)


Effect of heat on salts
■ Effect of heat on salts

A salt may dissociate to release certain gases. (Give information regarding the identity of the anion)

A salt may change in colour. (Give information regarding the identity of the cation)
■ This video contains information on the effects of heat on salts.
■ Gas tests (to identify the type of gas) :

Observation of the colour

Tested with damp blue litmus paper and damp red litmus paper

Tested with limewater

Tested with glowing wooden splinter

Tested with acidic potassium manganate(VII) solution
■ Characteristics and confirmatory tests for several gases.

Gas Colour Smell Confirmatory Test
Hydrogen Colourless Odourless Give 'pop' sound with lighted wooden splinter
Oxygen Colourless Odourless Lights up a glowing wooden splinter
Water vapour Colourless Odourless White anhydrous copper (II) sulphate turns blue
Carbon dioxide Colourless Odourless Turns limewater chalky
Ammonia Colourless Pungent Turns damp red litmus blue.
Produces thick white fumes with hydrogen chloride gas
Chlorine Greenish yellow Pungent Bleaches damp red litmus paper.
Turns damp blue litmus paper to red and the bleaches it.
Nitrogen dioxide Brown Pungent Turns damp blue litmus paper red
Sulphur dioxide Colourless Pungent Bleaches the purple colour of acidic potassium manganate (VII) solution
Hydrogen chloride Colourless Pungent Fumes with glass rod dipped in concentrated ammonia solution
■ Effects of heat on salts:

Carbonate ions
All carbonate salts (except Na2CO3 and K2CO3) will decomposes when heated to release carbon dioxide gas, CO2.
Example:
MgCO3(s)ΔMgO(s)+CO2(g)
CuCO3(s)ΔCuO(s)+CO2(g)

Nitrate salts
Sodium nitrate and potassium nitrate decomposes when heated to produce oxygen gas, and nitrites
Other metal nitrates produces oxygen gas, nitrogen dioxide gas and metal oxides when heated.
Example:
2NaNO3(s)Δ2NaNO2(s)+O2(g)
Zn(NO3)2(s)Δ2ZnO(s)+4NO2(g)+O2(g)

Sulphate salts
Most sulphate salts are not decomposed by heat.
Only a few sulphates such as iron(II) sulphate, zinc sulphate and copper sulphate decompose to sulphur dioxide or sulphur trioxide when heated.
Example:
2FeSO4(s)ΔFe2O3(s)+SO2(g)+SO3(g)
ZnSO4(s)ΔZnO(s)+SO3(g)
CuSO4(s)ΔCuO(s)+SO3(g)

Chloride salts
All chlorides salts are stable when heated except ammonium chloride.
Example:
NH4Cl(s)ΔNH3(s)+HCl(g)
■ Gas produced in heat test enable inferences to be made on the types of salts.

Type of gas produced Types of ion present
CO2 CO2-3 ion present (except Na2CO3 and K2CO3)
O2 NO-3 ion present
NO2 NO-3 ion present (except NaNO3 and KNO3)
SO2 sO2-4 ion present
NH3 NH-4 ion present
■ Residues in heat test enable inferences to be made on the types of salts.

Colour of original salts Colour of residue Inference
White Yellow when hot, white when cooled ZnO, presence of ion Zn2+
White Brown when hot, yellow when cooled PbO, presence of ion Pb2+
Blue/Green Black CuO, presence of ion Cu2+
Green/Yellow Brown Fe2O3, presence of ion Fe3+ or Fe2+


Test for anions
■ Anions that are normally tested in qualitative analysis:

Test for carbonate ions, CO2-3
All carbonates except K2CO3 and Na2CO3 release carbon dioxide when heated.
MgCO3(s)ΔMgO(s)+CO2(g)
All carbonates produce carbon dioxide when reacts with dilute acid.
MgCO3(s) + 2HCl(aq) → MgCl2 + H2O(l) + CO2(g)
Na2CO3(aq) + 2HCl(aq) → 2NaCl2 + H2O(l) + CO2(g)
This video shows the test for carbonate ions.


Test for nitrate ions, NO-3
All nitrates except NaNO3 and KNO3 give out brown gas, nitrogen dioxide and oxygen when heated. NaNO3 and KNO3 release oxygen when heated.
2NaNO3(aq) → 2NaNO2(aq) + O2(g)
2Mg(NO3)2(aq) → 2MgO(aq) + 4NO2(g) + O2(g)
This video shows the effects of heat on nitrate ions.
Brown Ring Test
About 2cm3 nitrate solution is mixed with dilute sulphuric acid and iron(II) sulphate solution in test tube.
Then a few drops of concentrated sulphuric acid are added slowly and carefully down the side of the test tube.
A brown ring is formed between the layers of concentrated acid and the nitrate mixture.
The brown ring, composed of a complex ion, confirm the presence of nitrate.
This video shows the Brown Ring test for nitrate ions.

Test for sulphate ions, SO2−4
About 2cm3 sulphate solution is mixed with dilute hydrochloric acid followed by barium chloride solution. A white precipitate, barium sulphate forms, confirming the presence of a sulphate.
Ba2+(aq) + SO2−4(aq) → BaSO4(s)
This video shows the test for sulphate ions.

Test for chloride ions
About 2cm3 of a chloride solution is mixed with dilute nitric acid followed by the silver nitrate solution.
A white precipitate, silver chloride forms, confirming the presence of a chloride.
Ag+(aq) + Cl(aq) → AgCl(s)
This video shows the test for chloride ions.

Laboratory Activity 8.2.1 :Test for anions
Test for cations
■ The following tests are conducted to identify cations in solutions:

Test with aqueous sodium hydroxide, NaOh (aq)

Test with aqueous ammonia, NH3 (aq)

Confirmatory tests with specific reagents.
■ This video contains information on the test for cations
■ Test with aqueous sodium hydroxide, NaOH (aq)

Colourless cation aqueous
Observation Inferences
Ammonia gas NH3 is released when heated up. NH4+ ions may be present.
White precipitate not soluble in excess NaOH solution Mg2+ or Ca2+ ions may be present.
White precipitate soluble in excess NaOH solution Zn2+ or Al3+ or Pb2+ ions may be present.

Coloured cation aqueous
Observation Inferences
Blue precipitate not soluble in excess NaOH solution Cu2+ ions may be present.
Green precipitate not soluble in excess NaOH solution Fe2+ ions may be present.
Brown precipitate not soluble in excess NaOH solution Fe3+ ions may be present.

This video contains information on the test for cations with NaOH
■ Test with aqueous ammonia, NH3(aq)

Observation Inferences
No reaction Na4+ or Ca2+ ions may be present.
White precipitate not soluble in excess NH3 solution Mg2+ or Al2+ or Pb2+ ions may be present.
White precipitate soluble in excess NH3 solution Zn2+ ions may be present.

Coloured cation aqueous
Observation Inferences
Blue precipitate soluble in excess NH3 solution forming dark blue solution Cu2+ ions may be present.
Green precipitate not soluble in excess NH3 solution Fe2+ ions may be present.
Brown precipitate not soluble in excess NH3 solution Fe3+ ions may be present.

This video contains information on the test for cations with ammonia solution
■ Confirmatory test for :

iron(II) ion, Fe2+ and iron(III) ion, Fe3+
Cation Potassium hexacyanoferrate(II), K4Fe(CN)6 Potassium hexacyanoferrate(III), K3Fe(CN)6 Potassium thiocyanate, KSCN
Fe2+ Light blue precipitate Dark blue precipitate No red solution
Fe3+ Dark blue precipitate Greenish brown precipitate Blood red solution

lead (II) ion, Pb2+
Cation Potassium iodide, KI Potassium chloride, KCl Potassium sulphate, K2SO4
Pb2+ Yellow precipitate
Pb2+ + 2I → PbI2
Dissolves in hot water when heated
White precipitate
Pb2+ + 2Cl → PbCI2
Dissolves in hot water when heated
White precipitate
Pb2+ + SO2−4 → PbSO4

This video contains information on the confirmatory test for cations

ammonium ion, NH4+
Brown precipitate formed with Nessler reagent.
■ Analysis qualitative summary of cations:

Cation NaOH(aq) NH3(aq) Na2CO3(aq) H2SO4 or Na2SO4(aq) HCl or NaCl (aq) Confirmatory test
Na+ Flame test - yellow flame
Al3+ White precipitate soluble in excess NaOH White precipitate soluble in excess NH3 White precipitate soluble in excess HNO3
Pb2+ White precipitate soluble in excess NaOH White precipitate soluble in excess NH3 White precipitate soluble in excess HNO3 White precipitate White precipitate soluble in hot water KI - yellow precipitate
KCL - white precipitate
Both soluble in hot water
Zn2+ White precipitate soluble in excess NaOH White precipitate soluble in excess NH3 White precipitate soluble in excess HNO3 White precipitate with potassium hyxacyanoferrate(II), K4Fe(CN)6
Mg2+ White precipitate soluble in excess NaOH White precipitate soluble in excess NH3 White precipitate soluble in excess HNO3
Ca2+ White precipitate soluble in excess NaOH No precipitate White precipitate soluble in excess HNO3 White precipitate
Cu2+ Blue precipitate soluble in excess NaOH Blue precipitate soluble in excess NH3 Blue precipitate Blue solution Blue solution Blue precipitate with potassium hyxacyanoferrate(III), K3Fe(CN)6
Fe2+ Dirty green precipitate insoluble in excess NaOH Dirty green precipitate soluble in excess NH3 Green precipitate Green solution Green solution Dark blue precipitate with potassium hyxacyanoferrate(III),K3Fe(CN)6
Fe3+ Brown precipitate soluble in excess NaOH Brown precipitate soluble in excess NH3 Brown precipitate Brown solution Brown solution Blood red solution with potassium thiocyanate, KSCN
NH4+ NH3 released upon heating Brown precipitate with Nessler's reagent
Laboratory Activity 8.2.2 : Qualitative analysis of salts


Flow chart for qualitative analysis of anion and cation
■ Qualitative analysis of a salt

To confirm the presence of the cation and anion of a named salt.

To identify the cation and anion of one or more unknown salts.

The animation below summarized the analysis of anions in salts.

The animation below summarized the analysis of cations in salts.


⇲ For exercise(objective and subjective), download for free on Android OS.

5.3 Medicines

Traditional medicine
■ Type of traditional medicines

Obtained from animals, plants and minerals without chemically processed.

The effectiveness depends on belief and experiences.

The knowledges are just passed from one generation to the next generation.
■ Example of traditional medicine

Source of traditional medicine Treatment method and uses
Aloe vera
Using its leaves to treat skin wounds and diseases
Garlic
Contains antibiotic properties that can treat high blood pressure, prevent cold and asthma.
Ginger
Using its leaves and rhizomes to prevent cold and remove stomach wind.
Ginseng
Using its root to make drinks so as to strengthen the body
Mint
Using its leaves to cure sore throats.
Pegaga
Using its leaves to treat depression and for longevity.
■ This video contains information regarding traditional medicine.


Types of modern medicine and their uses
■ Modern medicine

A substance that is chemically produced

Can be provided in various forms such as pills, capsules, paste, suspension and solution

Can be divided into :
Analgesics
Antibiotics
Psychotherapeutic drugs
■ This video contains information regarding analgesics.


Modern medicine-analgesics
■ Analgesics

Used to relieve pain.

Types of analgesics:
opiates that used to relieve internal pain.
non-opiates that used to relieve muscular and skeletal pains.
■ Example of analgesics:

Aspirin
To treat fever, relief pain such as headache, toothache and arthritic pain, to reduce inflammation and to reduce the ability of blood to clot.
Not suitable for pregnant mothers and children who have flu .

Paracetamol
To relieve mild to moderate pain such as headache, muscle and joint pains, period pain and fever.
It is not a very effective anti-inflammatory agent.
Can be given to children as it does not irritate the stomach.

Codeine
It is a stronger analgesic used in headache tablets and cough medicines.
It may cause drowsiness after taken.
Can be extracted from opium or synthesised from morphine.
■ Preparation of aspirin

Can be prepared by adding salicylic acid into ethanoic anhydride.
■ The video below shows the white crystals of aspirin are formed from the reaction between salicylic acid and ethanoic anhydride.


Modern medicine-antibiotic
■ Antibiotic

Used to kill or prevent the growth of bacteria.

Obtained from living organisms such as fungi and bacteria.
■ Example of antibiotic :

Penicillin
Extracted from fungus Penicillium notatum
A powerful antibiotic used to treat diseases caused by bacterial infections :
○ gonorrhea
○ syphilis
○ syphilis
○ pneumonia
○ meningitis

Streptomycin
Produced by soil bacteria of the genus Streptomyces
Used to treat :
○ tuberculosis
○ urinary infection
○ TB
○ pneumonia
■ This video contains information regarding antibiotic.


Modern medicine-psychotherapeutic drugs
■ Psychotherapeutic drugs

Used to treat some psychiatric and neurological problems

Psychotherapeutic drugs are classified into:
Stimulants
Antidepressant
Antipsychotic
■ Stimulants

Stimulates the central nervous system.

Speed up metabolic rate to make a person more active.

Increase pulse rate and blood pressure.

High doses or excessive use may cause sleeplessness, anxiety, hallucination or severe depression.
■ Example of stimulants:

Amphetamine
A strong and powerful synthetic stimulant that stimulates the central nervous system (nerves and brain).
Symptoms of an amphetamine overdose include restlessness, tremor, rapid breathing, confusion, hallucinations.

Cocaine
It is applied to certain areas of the body (for example, the nose, mouth, or throat) to cause loss of feeling or numbness.
May cause mental and physical problems.
■ Antidepressants

Used to reduce depression in depressed patients

Used to treat a psychotic diseases such as anxiety disorders, eating disorders, chronic pain and abnormal thoughts on killing himself.
■ Example of antidepressant drugs:

Barbiturates
It is used to sedate, calm or relax an individual.
It is used in sleeping pills to cure people who suffer insomnia.
Over dosage may cause death.

Tranquiliser
Used to calm a person reduce tension, anxiety and fear.
■ Antipsychotics

Used to treat psychiatric illness such as schizophrenia and mood disorder

Used to treat a patient that not aware of reality, auditory hallucinations (schizophrenia), or become angry easily.

Common antipsychotic medicines are chlorpromazine, reserpine, butyrophenones and clozapine.
■ This video contains information regarding psychotherapeutic drugs


Modern medicine-other medicine
■ Hormones and steroids

Crucial substances for the proper function of the body.

Produced and secreted into the bloodstream by endocrine glands in the body.
■ Example:

Insulin
A hormone produced from cells of the pancreas
Regulates the amount of sugar in the blood
Lack of insulin in the blood can cause diabetes mellitus

Cortisone
A steroid hormone released by the adrenal gland in response to stress.
Used to treat a variety of skin problems, asthma and arthritis.
■ This video contains information regarding other categories of modern medicine.


The side effects of medicine
■ Side Effects of Medicine

Patient should seek medical advice from a doctor to avoid any side effects

The table below shows the side effects of some medicines
Medicine Side effects
Aspirin Can cause bleeding and ulcers in the stomach and intestinal wall
Can cause unconsciousness
Antipsychotic drug May cause addiction
Can cause headache, confusion and a high rate of heart beat
Amphetamine May cause addiction
Can cause aggressiveness and hallucination
May develop sleeplessness
Barbiturate May cause addiction
Can cause death if overdose
Penicillin Can cause allergic reactions
May cause coma
■ This video contains information regarding the side effects of medicine.

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