Presentation is loading. Please wait.

Presentation is loading. Please wait.

Revision on soap and detergent Structure Cleansing action Compare soap and detergent.

Similar presentations


Presentation on theme: "Revision on soap and detergent Structure Cleansing action Compare soap and detergent."— Presentation transcript:

1 Revision on soap and detergent Structure Cleansing action Compare soap and detergent

2 the organic part the ionic part the hydrophobic part the hydrophilic part the head part the tail part STRUCTURE of SOAP PARTICLE STRUCTURE OF DETERGENT PARTICLE

3 CLEANSING ACTION OF SOAP OR DETERGENT. a) State three abilities of both soap and detergent that enable them to act as cleansing agents i.Ability to lower the surface tension of water This helps to wet the cloth better ii. To emulsify oil or grease, (break the oil or grease into smaller droplets) iii. Suspend oil or grease in water, Prevent the oil or grease from redeposit on the surface of the cloth

4

5 Describe the cleansing action of soap and detergent 1) Soap dissolves in water and lowers the surface tension of water. This helps to wet the cloth better 2) The hydrophobic part ( tail part) dissolves In grease, the hydrophilic part ( head part) dissolves in water 3) Movement of water during scrubbing helps to loosen the grease and lift the grease off the surface 4) Repulsion of negative charges break the grease into small droplets. Rinsing washes away these droplets and leaves the cloth clean

6 d)Compare and contrast the cleansing action of soap and detergents PropertySoapDetergent 1 sources 2 Molecular structure 3 Effectiveness in hard water 4 Effectiveness in acidic water 5 Cleaning power 6 Effect to the environment Made from plant or animalMade from petroleum fractions R – COO – Na + Where R is alkyl group R SO 4 – or Forms scum with hard water Does not form scum with hard water Forms precipitate with acidic water Does not form precipitate with acidic water Less powerfulMore powerful Biodegradable and do not cause any pollution Some detergents are non biodegradable and kill aquatic lives

7 Explain the difference Hard water contains Mg 2+ ions and Ca 2+ ions Detergent form soluble salt with Mg 2+ ions and Ca 2+ Detergent form soluble salt with Mg 2+ ions and Ca 2+ No scum is formed, No scum is formed, so detergent can function as cleaning agent so detergent can function as cleaning agent But soap form insoluble salt with Mg 2+ ions and Ca 2+ But soap form insoluble salt with Mg 2+ ions and Ca 2+ Scum is formed, Scum is formed, so soap cannot function as cleaning agent so soap cannot function as cleaning agent soap detergent

8 Revision on rusting of iron Conditions for rusting Describe process of rusting Effect of other metals on rusting of iron Ways to prevent rusting of iron

9 a)State conditions of rusting b) State the function of oxygen and iron in the rusting of iron b) Oxygen is the oxidizing agent and Iron is the reducing agent a)Presence of water and oxygen

10 DESCRIBE PROCESS OF RUSTING IN TERMS OF OXIDATION AND REDUCTION REACTION cathodecathode anode e Fe 2+

11 Step 1- At anode, iron atom is oxidized to form iron(II) ions to form iron(II) ions Step 2- Electron flow through metal to cathode where there are plenty of dissolved oxygen where there are plenty of dissolved oxygen - Electron are gained by Oxygen to form hydroxide ions Step 3- iron (II) ions combined with hydroxide ions to form iron(II) hydroxide Step 4- the iron(II) hydroxide rapidly oxidesed by oxygen to form RUST

12 Revision on Rusting of iron

13 Revision on Rusting of iron WHAT IS THE FUNCTION OF A)POTASSIUM HEXACYANOFERATE(III) SOLUTION)? B) PHENOLPHTHALEIN? C) AGAR? TO DETECT THE PRESENCE OF IRON(II) ION TO DETECT THE PRESENCE OF HYDROXIDE ION TO TRAP THE COLOUR FORMED DURING REACTION

14 A)WHY DOES THE PHENOLPHTAHLEIN CHANGE TO PINK IN IRON NAIL WITH MAGNESIUM? B)WHICH METAL UNDERGO CORROSION? C)WRITE HALF EQUATION FOR THIS REACTION D)WHAT IS THE ROLE OF MAGNESIUM IN THIS EXPERIMENT? Presence of OH- ion magnesium Mg  Mg 2+ + 2e To protect iron from rusting

15 Revision on Rusting of iron A)WHY DOES THE POTASSIUM HEXACYANOFERRATE(III) CHANGE TO BLUE IN IRON NAIL WITH COPPER? B)WHICH METAL UNDERGO CORROSION? C)WRITE HALF EQUATION FOR THIS REACTION D)WHAT IS THE ROLE OF COPPER IN THIS EXPERIMENT? Presence of Fe 2+ ion iron Fe  Fe 2+ + 2e To encourage rusting of iron

16 Revision on Rusting of iron A)WHAT IS THE ROLE OF METALS THAT ARE IN CONTACT with iron IN THE RUSTING OF IRON? Metals which are above iron in ECS inhibit iron from rusting Metals which are below iron in ECS encourage rusting of iron

17 Ways to prevent RUSTINg of iron Alloying In stainless steel Iron is alloyed with carbon, chromium and nickel Chromium and nickel forms a layer that does not rust Sacrificial protection Iron is connected to a more electropositive metal, example magnesium or zinc Mg or Zinc will corrode first, so protect iron from rusting Galvanising iron or steel is coated with a thin layer of zinc When scratched, zinc will corrode first because zinc is more electropositive than iron Tin plating sheets of steel are coated with a thin layer of tin But if scratched, iron will rust, because tin is less electropositive than iron

18 Explain the difference

19 In test tube 1 Blue colour shows presence of Fe 2+ ions Iron nail rusts, due to presence of water and oxygen Fe  Fe 2+ + 2e

20 In test tube 2 High intensity of pink colour shows high conc of OH – ions High intensity of pink colour shows high conc of OH – ions NO rusting of iron occur, Magneium undergo corrosion NO rusting of iron occur, Magneium undergo corrosion Mg is more electropositive than iron, so protect iron from rusting Mg is more electropositive than iron, so protect iron from rusting Mg  Mg 2+ + 2e

21 In test tube 3 High intensity of blue colour shows high conc of Fe 2+ ions High intensity of blue colour shows high conc of Fe 2+ ions Iron nail rusts, Iron nail rusts, Copper is less electropositive than iron, so Copper is less electropositive than iron, so Copper encourage rusting of iron Copper encourage rusting of iron Fe  Fe 2+ + 2e

22 Revision of Rubber and coagulation of latex How coagulation of latex occur Vulcanisation of rubber

23 LATEX BEFORE ACID IS ADDED Rubber molecules repel each other No coagulation occur ADD ACID, or bacteria acts on latex to produce lactic acid. (H + IONS) neutralize the negatively charged of rubber articles Rubber particles collide Rubber membranes rapture rubber molecules combine, coagulation occur HOW coagulation of latex occur

24 VULCANISED RUBBER a) What is meant by vulcanization of rubber? ADDITION OF SULPHUR TO RUBBER AT 140 O C AND HIGH PRESSURE IN THE PRESENCE OF ZINC OXIDE AS THE CATALYST By heating latex with SULPHUR or a solution of sulphur monochloride in methylbenzene as solvent b) In industry, how does the vulcanization of rubber is carried out?

25 C) DESCRIBE HOW SULPHUR ATOMS CHANGE THE PROPERTIES OF RUBBER In vulcanization …………..atoms form …………………between rubber molecules These …………………….prevent rubber……………………… from sliding too much when …………………………….The rubber molecules return to their ………………... position after being stretched. d) Draw cross-linkage of sulphur sulphur cross-link cross – LINK MOLECULES STRETCHEDORIGINAL

26 E) COMPARE AND CONTRAST THE PROPERTIES OF VULCANIZED AND UNVULCANISED RUBBER DifferencesVulcanisedUnvulcanised rubber Elasticity Hardness Tensile strength Resistance to heat Effect of organic solvents Differences Both are ELASTIC Both do not CONDUCT HEAT AND ELECTRICITY More elasticLESS elastic HarderSOFTER More tensile strengthLESS tensile strength More resistance to heatLESS resistance to heat LESS SOLUBLEMORE SOLUBLE Similarities

27 G) STATE ONE ADVANTAGE OF NATURAL RUBBER OVER SYNTHETIC RUBBER Natural rubber is made from latex of rubber tree Synthethic rubber is man-made rubber from chemical substance F) WHAT IS THE DIFFERENCE BETWEEN NATURAL RUBBER OVER SYNTHETIC RUBBER IN TERMS OF SOURCE ? Only natural rubber can absorb the high STRESS, STRENGH AND HEAT ………( in tyres) produced during landing and taking off of an aero plane


Download ppt "Revision on soap and detergent Structure Cleansing action Compare soap and detergent."

Similar presentations


Ads by Google