Chemistry Folio Chapter 9 Spm

Hafiz Akmal 1 CHEMISTRY FOLIO chapter 9: Manufacture Substances in industry

SULPHURIC ACID

USES OF SULPHURIC ACID

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Figure 1:- Uses of Sulphuric Acid, H2SO4

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MANUFACTURE OF SULPHURIC ACID The manufacture of sulphuric acid in industry is through the contact process. • The raw materials used to manufacture the acid are sulphur, air and water. • The acid is produced in 3 stages:•

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STAGE 1: THE PRODUCTION OF SULPHUR DIOXIDE

a) This can be obtained through two methods:a) Heating liquid sulphur with hot air in a furnace. S (s) + O2 (g) SO2 (g) b) Heating sulphides in air, for example: 4FeS2 (s) + 11O2 (g) 2Fe2O3 (s) + 8SO2 (g) SO2 is a side-product in the extraction of the metal, iron. [Fe2O3 is reduced to iron with coke] Zinc pyrites can also be heated in air as follows: 2ZnO (s) + 3O2 (g) 2SO2 (g) + 2ZnO (s)

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STAGE 2: FORMATION OF SULPHUR TRIOXIDE

Pure, dry sulphur dioxide is mixed with dry oxygen in excess and passed over vanadium(V) oxide, V2O5 as catalyst at a temperature of 450˚C - 550˚C and a pressure of 1 atmosphere. The conditions ensure the maximum production of sulphur trioxide: 2SO2 (g) + O2(g) 2SO3 (g) b) The reaction takes place in a heat converter. c) Excess air is used to ensure higher percentage of SO3 produced. a)

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STAGE 3: FORMATION OF SULPHURIC ACID

The sulphur trioxide is dissolved in concentrated sulphuric acid to form a product called oleum, H2S2O7. This is carried out until the concentrated sulphuric acid has reached a concentration of 99.5%. SO3 (g) + H2SO4 (aq) H2S2O7 (l) b) The product, oleum will not show any property of an acid. This is because, oleum will ‘not ionise’ without the presence of water. c) Water is then added to the oleum to produce concentrated sulphuric acid. H2S2O7 (l) + H2O (l) 2H2SO4 (l) d) The reaction in (a) and (b) is equivalent to dissolving sulphur trioxide in water. SO3 (g) + H2O (l) H2SO4 (aq) e) However, this reaction is not carried out in industry. This is because the reaction is too vigorous. f) It produces a large cloud of sulphuric acid mist. This mist is corrosive and pollutes the air. a)

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CONTACT PROCESS: Water

Concentrated H2SO4

O2 , V2O5, 450˚C, 1 atm Burnt in air

Figure 2:- Flow chart of Contact Process

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The industrial process in the Manufactured of Sulphuric Acid

USES OF AMMONIA IN INDUSTRY:

Hafiz Akmal 9 CHEMISTRY FOLIO chapter 9: Manufacture Substances in industry Examples are ammonium sulphate, ammonium nitrate and urea. The first two are prepare through neuralisation urea is produced Havingbut a low melting point, by the reaction of ammonia with carbon dioxide. Theliquefied reaction ammonia involved are as the makes a following: a) 2NH3 (g) + H2SO4(aq) good cooling (NH4)2SO 4(s) in ammonium sulphate agent b) NH3 (g) + HNO3(aq) refrigerators NH4NO (aq) ammonium nitrate 3 and air c) 2NH3 (g) + CO2(g) (NH2)2CO (s) + H2O (l) urea conditioners. It neutralizes the organic acids formed by microorganisms in latex, thereby preventing coagulation and preserving the latex in liquid form. Ammonia is converted to nitric acid in the Ostwald process: 1) ammonia is first oxidised to nitrogen monoxide, NO, by oxygen in the presence of platinum as catalyst at 900˚C. 4NH3 (g) + 5O2(g) Pt/900˚C 4NO (aq) + 6H2O (l) 2) nitrogen monoxide is further oxidised to nitrogen dioxide. 2NO (g) + O2(g) 2NO2 (g) 3) Nitrogen dioxide and oxygen are dissolved in water to produced nitric acid. 4NO2 (g) + O2 (g) + H2O (l) 4HNO3 (aq) a) Nitric acid is manufactured from ammonia before being used to make explosive like trinitrotoluene (TNT). b) Nitric acid, in this case, is reacted with organic substances like toluene.

EXPERIMENT TO INVESTIGATE THE PROPERTIES OF AMMONIA Aim:• To investigate the properties of ammonia

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Material:•

0.1 mol dm ammonia solution, 0.1 mol dm sodium hydroxide solution, ammonia chloride, calcium hydroxide, concentrated hydrochloric acid, soda lime, distilled water, red litmus paper, Ph paper.

Apparatus:• Test tubes, beaker, U-tube, Bunsen burner, glass rod, delivery tube, stoppers.

Procedure:a) Preparation of ammonia gas: 1. Some ammonium chloride is mixed with some calcium hydroxide. 2. The apparatus as shown in Figure 3 is set up

3. The mixture is heated 4. The ammonia gas produced is collected in a few test tubes. The test tubes containing ammonia gas must be closed with stoppers.

b)

Alkalinity of ammonia: 1. 5.0 cm of 1 mol ammonia solution and 5 cm of 0.1 mol dm sodium hydroxide solution are poured into two separate test tubes.

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2. A piece of pH paper is dipped into the solution in each test tube. 3. The pH values of both solution are recorded.

c)

Colour, physical state, smell and solubility of ammonia: 1. The colour and physical state of ammonia are observed. 2. The stopper of a test tube containing ammonia gas is removed and the smell of the gas is identified. 3. A test tube containing ammonia gas is inverted into a beaker of water. 4. All observation are recorded.

d) Density of ammonia: 1. A test tube containing ammonia gas is held upright and another test rube containing ammonia gas is held upside down. 2. The stopper of the two test tubes are removed. 3. After 20 seconds, a piece of moist red litmus paper is put at the mouth of each test tube as shown in figure 5. 4. The colour of the red litmus paper is recorded.

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e) Chemical property of ammonia: 1. One end of a glass rod is dipped into concentrated hydrochloric acid. 2. The glass rod is then put on top of a test tube of ammonia gas. 3. Any change taking place is observed.

Observation :Section

b)

c)

Observation • pH of ammonia solution is 10 • pH of sodium hydroxide solution is 14 • colourless gas

Inference • ammonia is weak alkali • sodium hydroxide is a strong alkali • ammonia is a colourless

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d)

e)

• pungent smell • water rushed up and fills up the whole test tube • moist red litmus paper on top of the upright test tube does not change colour. • Moist red litmus paper under the inverted test tube turns blue

• Dense white fumes are formed

gas with a pungent smell • ammonia is very soluble in water

• Ammonia gas has escaped from the upright test tube and thus is slightly less dense than air

• Ammonia react with hydrogen chloride gas to form ammonium chloride

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Discussion:• Ammonia is a weak alkali and has a pH of 10 • Ammonia is a colourless gas with a pungent smell • Ammonia is very soluble in water, ionize partially in water to form ammonium ions and hydroxide NH3 (g) + H2O (l) = NH4+ (aq) + OH- (aq) • Ammonia is slightly less dense than air • Ammonia react with hydrogen chloride gas to form ammonium chloride NH3 (g) + HCl (g) = NH4Cl (s)

Conclusion:• Ammonia is an alkaline, colourless gas with a pungent smell. It is very soluble in water and is less dense in than air. It react with hydrogen chloride gas to form dense white fumes of ammonium chloride

HABER PROCESS

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The man ufac ture of am mon ia thro ugh the Hab er Proc ess

PREPARATION OF AMMONIA FERTILISER Aim:•

To prepare ammonium sulphate.

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Material:•

1 mol dm-2 sulphuric acid, 2 mol dm-3 ammonia solution, methyl orange, filter paper

Apparatus:• 25.0 cm pipette, burette, conical flask, white tile, retort stand and clamp, beaker, glass rod, evaporating dish, filter funnel, Bunsen burner, tripod stand, wire gauze.

Procedure:a) Determining the volume of sulphuric acid that will neutralize 25.0 cm of ammonia solution:-3 1. 25.0 cm of 2 mol dm ammonia solution is transferred by a pipette to a clean conical flask. 2. Three drops of methyl orange indicator are added to the alkali. The solution turns yellow.

A clean burette is filled with 1 mol dm-2 sulphuric acid and clamped to a retort stand. The initial burette reading is recorded. 4. The conical flask with its content is placed on a white tile below the burette as shown in figure 6 below. 3.

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5. The sulphuric acid is added slowly into the conical flask. The conical flask is swirled gently throughout the titration. 6. The addition of sulphuric acid is stopped when the indicator changes from yellow to orange. The final burette reading is recorded. 7. The volume of acid needed to completely neutralize the 25.0 cm of 2 mol dm-3 ammonia solution is calculated. Let this volume V cm.

b) Preparation ammonium sulphate salt:-

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25.0 cm of 2 mol dm-3 ammonia solution is pipetted into a clean conical flask. No indicator is added. 2. V cm of 1 mol sulphuric acid is added from the burette to the ammonia solution. 3. The mixture in the conical flask is transferred to an evaporating dish and heated until a saturated solution is formed. 4. The hot, saturated salt solution is left to cool for crystallization to occur. 5. The crystal of ammonium sulphate formed are filtered, ashed and dried between sheets of filter paper. 1.

Observation:• A colourless solution is formed when sulphuric acid is added to ammonia solution. • The crystal obtained are white in colour

Discussion:• The equation for the reaction is: H2SO4 (aq) + 2NH4OH (aq) (NH4)2SO4 (aq) + 2H2O (l) • Methyl orange is an acid-base indicator used to determine the end point of the titration. • The first titration is carried out to determine the exact volume of sulphuric acid required to completely neutralize the 25.0 cm of ammonia solution.

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• The salt solution in the first titration is discarded because it is contaminated by methyl orange. • The ammonium sulphate solution should not be heated until dryness because ammonium sulphate decomposes when it is overheated. • The weight of ammonium sulphate obtained from the activity is always less than the theorical value. This is because some of the salt is not fully crystallized out and still remains in the solution. • Other ammonium salt such as ammonium nitrate can be prepared from the reaction between nitric acid and ammonium solution.

Conclusion:• Ammonium sulphate and other ammonium fertilizers can be prepared by neutralizing ammonia solution with the respective acids.

THE PHYSICAL PROPERTIES OF PURE METAL

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PROPERTIES OF AMMONIA

•

•

Ammonia turns the damp red litmus paper blue. The gas is less dense than air

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•

•

An inverted filter funnel is used to prevent sucking back of water

•

Ammonia gas burns in oxygen to produce nitrogen monoxide gas

4NH3 + 5O2

4NO + 6H2O

ALLOY Meaning and purpose of making alloy:-

Aqueous solutions of ammonia react with metal ions (except Na+, K+, and Ca2+) to produce precipitate of metal hydroxide

Ammonia is weak alkali which reacts with dilute acids in neutralization to produce salt.

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• Alloying is a process of mixing two or more metals (or mixing metals with element such carbon) which cannot be separated using physical way

Arrangement of atoms in alloys:-

Pure metal A

Pure metal B

COMPARE THE HARDNESS OF A PURE METAL AND ITS ALLOYS Alloys

Aim:• To compare the hardness of a pure metal and its alloy.

Problem Statement:-

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Are alloys harder than pure metal ?

Hypothesis:• Bronze is harder than cooper.

Variables:• Manipulated: Different types of materials (cooper & bronze) • Responding: diameter of the dent • Controlled: diameter of steel ball bearing, height of the weight, mass of the weight.

Operational definition:1)If the diameter of the dent is smaller, then the material is harder

Materials:2)Cooper block, bronze block, cellophane tape

Apparatus:3)Retort stand and clamp, 1-kg weight, metre ruler, steel ball bearing, thread.

Procedure:1)A steel ball bearing is taped onto a cooper block using cellophane tape. 2)A 1-kg weight is hung at a height of 50 cm above the cooper block as shown in the figure 8.

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3)The weight is allowed to drop onto the ball bearing. 4)The diameter of the dent made by the ball bearing on the cooper block is measured. 5)Steps 1-4 are repeated twice on the other parts of the cooper block in order to obtain an average value for the diameter of dents formed. 6)Steps 1-5 are repeated using a bronze block to replace the cooper block. 7)The reading are recorded in the table.

Results:-

DIAMETER OF THE DENT (mm) 2 3 average

METAL

1

Cooper

2.9

2.8

2.9

2.9

Bronze

2.1

2.2

2.2

2.2

Discussion:1)

The smaller the diameter of the dent, the harder and stronger is the material.

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2)The average diameter of the dent made on the surface on the cooper block is bigger than the bronze block. 3)Based on the result, bronze is harder than cooper.

Conclusion:• The hypothesis is accepted.

EXAMPLE OF ALLOYS

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Bronze

Pewter

steel

Stainless steel

THE RATE OF RUSTING OF IRON, STEEL, AND STAINLESS STEEL Aim:-

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• To compare the rate of rusting of iron, steel and stainless steel.

Problem statement:• How does the rate of rusting of iron, steel and stainless steel differ?

Hypothesis:• Iron rust faster than steel, and steel rust faster than stainless steel.

Variables:• Manipulated variable: Different types of nails • Responding variable: Intensity & amount of blue colour • Controlled variable: Size of nails, concentration of solution used, durations for rusting.

Operational definition:• The more intense the blue colour formed, the higher is the rate of rusting.

Materials:• Iron nail, steel nail, stainless steel nail, jelly solution, potassium hexacyanoferrate(lll) solution, water, sandpaper.

Apparatus:• Test tubes, test tube rack.

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Procedure:The nails are rubbed using sandpaper to remove the rust from the surface of the nails. 2)The iron nail placed in the test tube A, the steel nail in test tube B and the stainless steel nail in test tube C. 3) A 5% jelly solution is prepared by adding 5 g of jelly into 100 cm of boiling water. A few drops of potassium hexacyanoferrate(lll) solution are then added to the jelly solution. 4)The hot jelly solution is poured into the three test tubes until all the nails are fully immersed. 1)

The test tubes are placed in a test tube rack and left aside for three days. The intensity of the blue colour is observed. 6)All observation are recorded in the table. 5)

Observation:Test tube A B C

Intensity of blue colour Very High Low Nil

Inference Rusting occurs very fast Rusting occurs slowly No rusting occurs

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Discussion:When iron rust, each iron atom loses two electrons to form an iron(ll) ion, Fe2+. Fe (s) = Fe2+ (aq) + 2e- (aq) 2)Potassium hexacyanoferrate(lll) solution is added to the jelly solution as an indicator to detect iron(ll) ions. 3)When there is iron(ll) ion, potassium hexacyanoferrate(lll) solution will form dark blue colouration. 4)The higher the intensity of the blue colour, the higher is the rate of rusting. 5) Solidified jelly solution is used to trap and see the blue colouration clearly. This is because diffusions occurs the slowest in solids. 6)Based on the observation, iron rust faster than steel. Stainless steel does not rust. 7)The nail made from stainless steel does not rust. This is because this nail is an alloy of iron with carbon, chromium and nickel. 1)

8)The nail made from steel will rust slowly. The presence of carbon atoms will make the steel stronger than iron but does not prevent it from rusting.

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9)Rusting of iron is an example of corrosion. When corrosion occurs, the metal loses electrons to form metal iron.

Conclusion:• Iron rust faster than steel. Stainless steel does not rust. Hypothesis is accepted.

COMPOSITONS OF ALLOYS & THEIR USES

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Alloy Cupronic kel

Compositi on

Properties

Cu 75%

Hard, strong, resist corrosion

Coins

Light, strong

Aeroplane part, electric cables racing bicycles

Hard, strong, cheap

Vehicles, bridges, buildings

Hard, rust resistant

Kitchen appliance, watches, knifes, fork, spoons, machine parts

Ni 25%

Uses

Al 95% Duralumi n Steel

Stainless steel

Cu 4% Mg 1% Fe 99% C 1% Fe 73% Cr 18% Ni 8% C 1% Cu 90%

bronze

Sn 10% Cu 70%

Brass Solder

Pewter

Magnaliu m

Zn 30% Pb 50% Sn 50% Sn 91% Sb 7% Cu 2% Al 70% Mg 30%

Hard, strong, shining Harder and cheaper than Cu Low melting point, strong Malleable, ductile, rust resistant Light, strong

Decorative items, medals, artwork, pots & pans Musical instrument, bell, nails, screw, and pots Welding, soldering work Decorative items,souvenirs Tyre rim of racing car, skeletal body of aeroplane

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POLYMER

NATURAL POLYMER

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• •

Monomer acid amino Eg: in muscle, skin, silk, hairs, wools, and furs

• •

Monomer glucose Eg: in starch and cellulose

•

Monomer isoprene (2-methylbuta-1,3 diene) • Eg: in latex

SYNTHETIC POLYMER & IT USES • Synthetic polymers are polymers made in industry from chemical substances.

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• Many of the raw materials for synthetic polymers are obtained from petroleum, after refining and cracking process.

WHY USE SYNTETIC POLYMERS IN DAILY LIFE?

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ENVIRONMENTAL POLLUTION RESULTING FROM THE DISPOSAL OF SYNTHETIC POLYMERS

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GLASS Glass:•

The major component of glass is silica or silicon dioxide, SiO2 which found in sand.ri

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TYPES, COMPOSITION, PROPERTIES, AND USES OF GLASS GLASS

COMPOSITI ON

PROPERTIES •

SiO2 – 70% Soda lime glass

Na2O – 15% CaO – 10% Others – 4%

Lead glass

SiO2 – 70%

•

• • •

•

Low melting point Mouldable into shapes Cheap Breakable Can withstand high heat High density

USES •

•

Glass container Glass panes Mirror Lamps and bulbs Plates and bowls Bottles

•

Containers for

• • • •

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(crystal)

Na2O – 20% PbO – 10%

• • •

• SiO2 – 80% Borosilicate glass (Pyrex)

B2O3 – 13% Na2O – 4% Al2O3 – 2%

• •

•

Fused silicate glass

SiO2 – 99%

• •

B2O3 – 1% •

and refractive index Glittering surface Soft Low melting point (600˚C) Resistant to high heat &chemical reaction Does not break easily Allow infra-red rays but no ultra-violet rays High melting point (1700˚C) Expensive Allow ultraviolet to pass through Difficult to melt or mould into shape

CERAMICS Ceramics:-

• • • •

•

•

• •

drinks and food Decorative glass Crystal glassware Lens for spectacles Glass apparatus in lab Cooking utensils

Scientific apparatus like lens on spectrometer Optical lens Lab apparatus

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• Ceramic is manufactured substances made from clay that is dried, and heated in a kiln at a very high temperature • The main component of clay is aluminosilicate (aluminum oxide and silicon dioxide) with small quantities of sand and feldspar. Unlike glass, ceramic cannot be recycled. • Kaolinite is a high quality white clay that contains hydrated aluminosilicate, Al2O3•2SiO2•2H2O.

THE DIFFERENT CLASES OF CERAMIC

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GROUP Mineral Cement material Oxide of ceramic

COMPOSITION Quartz – SiO2 Calcite – CaCO3 Mixture of CaSiO3 and ammonium silicate Aluminium oxide – Al2O3 Silicon dioxide – SiO2

Non-oxides of ceramic

Magnesium oxide – MgO Silicon nitride – Si3N4 Silicon carbide – SiC Boron nitride – BN Boron carbide – B4C3

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THE USES OF IMPROVED GLASS AND CERAMICS FOR SPECIFIC PURPOSES

COMPOSITE MATERIALS

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• A composite material is structural material formed by combining two or more materials with different physical properties, producing a complex mixture. • They are used to make various substances in daily life because of the following reasons:a)Metals corrode and are ductile and malleable b)Glass and ceramic break easily c)Metal are good conductors but have high resistant, leading to loss of electrical energy as heat. d)Plastic and glass can withstand heat to a certain level only

COMPOSITE MATERIAL

COMPONEN T

PROPERTIES OF

PROPERTIES OF COMPOSITE

USES

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COMPONENT

•

concrete

•

hard but brittle low tensile strengh

•

Reinforced concrete

•

steel

•

strong in tensile strength expensive can corrode

• •

• • • • •

•

•

• • Superconductor

•

•

Cooper( ll) oxide Yttrium oxide Barium oxide

Glass

•

• •

•

Photochromic glass

Fibre optics

•

Silver chloride or silver bromid e

•

Glass with low refracti on

•

Insulator of electricity

Transparen t Not sensitive to light Sensitive to light

stronger higher tensile strength does not corrode easily cheaper can be moulded into shape can withstand very high applied force can support very heavy load • Conducts electricity without resistance when cooled by liquid nitrogen •

•

•

•

Transparen t Does not reflect light rays

• •

Reduce refraction of light Control the amount of light passed through it auto. Has the ability to change colour and become darker when exposed to ultraviolet light Low material cost Reflect light rays and allow to

•

construction of road rocket launching pads high-rise buildings

• •

•

• • • •

•

• •

•

Magnetically levitated train Transformer Electric cable Computer parts Information display panels Light detector device Car windshields Optical lens

Transmit data using light waves in telecommuni

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•

Glass with higher refracti ve index

•

glass

• • •

Fibre glass

•

polyest er plastic

• • • •

high density strong but brittle nonflexible light flexible inflammabl e elastic but weak

• • • • • • • •

travel along the fibre Can transmit electronic data or signal, voice and image

high tensile strength moulded and shaped inert to chemicals light, strong, tough nonflammable impermeable to water resilient flexible

cations

• • • • •

car bodies helmets skies rackets furniture