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SET 1 – POPULAR EQUATIONS IN CHEMISTRY

Chemical Formulae

1. Write the symbol for the element. No.

ELEMENT SYMBOL No. ELEMENT SYMBOL

1. Hydrogen 21 Sodium

2. Helium 22 Magnesium

3. Lithium 23 Aluminum

4. Beryllium 24 Silicon

5. Boron 25 Phosphorus

6. Carbon 26 Sulfur

7. Nitrogen 27 Chlorine

8. Oxygen 28 Argon

9. Fluorine 29 Potassium

10. Neon 30 Calcium

11. Vanadium 31 Nickel

12. Chromium 32 Cuprum

13. Manganese 33 Zink

14. Iron 34 Silver

15. Cobalt 35 Tin

16 Bromine 36 Barium

17 Iodine 37 Rubidium

18 Platinum 38 Krypton

19 Aurum 39 Xenon

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20 Lead 40 Mercury

2. Write the ionic formulae of the ions.

NO ION FORMULA NO ION FORMULA

1. Lithium ion 17 Oxide ion

2. Sodium ion 18 Bromide ion

3. Magnesium ion 19 Chloride ion

4. Potassium ion 20 Iodide ion

5. Calcium ion 21 Hydroxide ion

6. Aluminum ion 22 Sulphate ion

7. Iron (III) ion 23 Fluoride ion

8. Zinc ion 24 Nitrate ion

9. Copper (II) ion 25 Carbonate ion

10. Ammonium ion 26 Phosphate ion

11. Iron (II) ion

12. Tin ion

13. Lead(II) ion

14. Barium ion

15. Hydrogen ion

16. Silver ion

3. Write the chemical formulae of the substances below:

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NO SUBSTANCE CHEMICAL

FORMULA

NO SUBSTANCE CHEMICAL

FORMULA

1. Calcium carbonate 17 Silver nitrate

2. Magnesium nitrate 18 Potassium nitrate

3. Copper(II) sulphate 19 Sodium carbonate

4. Zink chloride 20 Sodium sulphate

5. Sodium hydroxide 21 Lead(II) iodide

6. Magnesium oxide 22 Lead(II) nitrate

7. Magnesium chloride

23 Potassium nitrate

8. Barium hydroxide 24 Potassium hydroxide

9. Barium sulphate 25 Calcium chloride

10. Copper(II) carbonate

26 Copper (II) sulphate

11. Iron(II) oxide 27 Hydrochloric acid

12. Iron(III) oxide 28 Sulphuric acid

13. Zink nitrate 29 Nitric acid

14. Ammonium chloride

30 Calcium carbonate

15. Ammonium sulphate

31 Carbon dioxide

16. Potassium

sulphate

32 Ammonia

Popular chemical equations .

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Reactions equations

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1 Magnesium reacts with oxygen

2 Copper oxide reacts with hydrogen

3 Lithium reacts with water

4 Sodium reacts with chlorine

5 Chlorine reacts with water

6 Iodine reacts with sodium hydroxide

7 Ionization of hydrochloric acid in water

8 Reaction of nitric acid with zinc

9 Reaction of sulphuric acid with copper(II)oxide

10 Reaction of hydrochloric acid with marble chips

11 Manufacture of sulphuric acidStage 1

Stage2

Stage 3

Stage 4

12 Reaction to produce ammonia in Haber Process

13 Reaction of sodium thiosulphate and sulphuric acid

14 Decomposition of hydrogen peroxide in the presence of catalyst

Reactions equations15 Combustion of methane in

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excess oxygen

16 Combustion of ethane in excess oxygen

17 Combustion of ethanol in excess oxygen

18 Reaction of ethene with hydrogen

19 Reaction of ethene with steam

20 Reaction of ethene with bromine

21 Reaction of ethene with hydrogen chloride

22 Dehydration of ethanol

23 Oxidation of ethanol to form ethanoic acid

24 Esterification of ethanol with propanoic acid

25 Displacement of copper from copper(II) sulphate by zinc

26 Displacement of iodine from potassium iodide by chlorine

27 Rusting of iron

28 Heating magnesium in the presence of potassium manganate(VII) powder

29 Precipitation reaction of silver chloride from its ions in solution

30 Word equation to prepare soap from saponification process

31 General formula of soap

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32 General formula of detergent

POPULAR half –equations in chemistry

Reactions Half equations at anode

Half equations at cathode

1 Electrolysis of molten lead(II) iodide

2 Electrolysis of 0.001 moldm-3 hydrochloric acid

3 Electrolysis of 1.0 moldm-3 hydrochloric acid

4 Electrolysis of 1.0 moldm-3 copper(II) sulphate solution using carbon electrodes

5 Electrolysis of 1.0 moldm-3 copper(II) sulphate solution using copper electrodes

Half equations at Negative electrode

Half equations at Positive electrode

1 Reactions in Daniel cell

(sketch diagram first)

REDOX REACTIONS Half equations for Oxidation

Half equations for Reduction

1 Reaction of iron(II) sulphate with chlorine

Overall equation

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2 Reaction of iron(III) chloride with zinc

Overall equation

3 Reaction of potassium iodide with acidified potassium manganate (VII) solution

Overall equation

4 Reaction of potassium bromide with acidified potassium dichromate(VI) solution

Overall equation

IONIC EQUATIONS

Reactions Ionic equation

1 Hydrochloric acid and magnesium

2 Hydrochloric acid and zinc

3 Sulphuric acid and marble chips

4 Precipitation reaction of silver chloride salt

5 Formation of barium sulphate salt

6 Displacement of copper from its ion by zinc

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7 Reaction of sulphuric acid and sodium hydroxide

8 Reaction of nitric acid and potassium hydroxide

EXERCISES

1. CuCO3 → CuO + CO2

Copper (II) carbonate is decomposed when heated strongly as shown in the equation above. Find the mass of copper (II) oxide formed when 12.4 g of copper (II) carbonate is heated completely. [RAM: Cu,64; O,16; C,12]

2. 720 cm3 of propane gas burns in excess oxygen at STP. Find the mass of carbon dioxide formed. [RAM: C,12; H,1; O,16]

3. Excess calcium carbonate reacts with 25 cm3 of 0.15 mol dm-3 hydrochloric acid. Calculate the volume of carbon dioxide gas released at room conditions. [Molar volume: 24 mol dm-3 at room conditions]

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4. H2O2 → H2O + O2

(i) Balance the equation above.

(ii) Find the number of moles of H2O2 that decomposes if 11.2 dm3 oxygen gas is

collected at STP. [RAM: H,1; O, 16; Molar volume : 22.4 dm3 mol-1 at STP]

5. The following equation is not balanced.

Na2SO4 + BaCl2 → BaSO4 + NaCl

(a) Identify the reactants and products of the reaction.

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(b) Balance the equation. Then, calculate

(i) the number of moles of sodium sulphate that react completely with a solution containing 2.08 g of barium chloride

(ii) the mass of barium sulphate formed when 1 mol of sodium sulphate is reacted with 1 mol of barium chloride

1)

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Refer to the diagram above:

Cell P Cell Q

Electrode M

Electrode N Electrode R Electrode S

Name of cell

Label anode and cathode

State products

State observations

Write ionic equations

State change of energy

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Answer the following questions

Electrode P Electrode Q

a) State all ions present

b) Label anode and cathode

c) State ions attracted to

d) State ions discharged

e) State products and what is the factor involved?

f) Give a reason why you have the product as mentioned above?

g) Write ionic equations

h) State observations and how do you test the products?

i) If the experiment is repeated with

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concentration of solution 0.001 mol dm-3. State the products . And what is the factor involved?

3) Organic reaction

A) Refer to the above reaction:

Reactions 1 2 3

a) Name of reactions

b) Reagents used

c) Conditions (if any)

d) Equations

Reactions 4 5 6

a) Name of reactions

Ethene

ethanol

Ethyl ethanoate

CO2 + H2O

Ethanoic acid

Reaction 2Reaction 1

Reaction 4

Reaction 3Reaction 5Reaction 6

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b) Reagents used

c) Conditions (if any)

d) Equations

B) Draw diagram for experiment to carry out for reaction 2

4) DESCRIBE THE COAGULATION OF LATEX when exposed to air

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5) A student obtained the following data to determine heat of precipitation of lead(II) sulphate (VI), PbSO4

Solution Volume (cm3) Concentration (moldm-3)

Initial temperature (oC)

Lead(II) nitrate 50 0.5 27.4Sodium sulphate 50 0.5 27.6

Highest temperature = 30.5 oC

a) What is meant by heat of precipitation? …………………………………………………………………………………..………………………………………..…………………………………………………………………………………………………………………………………..

b) Using data above, calculate heat of precipitation of lead (II) sulphate [Specific heat capacity 4.2 J g-1 o C-1 , density of solution , 1g cm-3 ]

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c) Write thermo chemical equation ……………………………………………………………………………

d) Write the ionic equation …………………………………………………………………………………………

e) Construct energy level diagram

…………………………………………………………………………………………….f) The experiment is repeated, using potassium sulphate to replace sodium

sulphate, with other conditions remain constant, and it was found that heat of precipitation of lead(II) sulphate is the same. Explain

………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………………

6) A student carried out an experiment to determine heat of displacement of copper from copper (II) sulphate solution . He added excess zinc powder to 50 cm3 of 0.20 mol dm-3 of copper(II) sulphate solution. The thermo chemical equation is shown below

Zn + Cu 2+ Cu + Zn 2+ ∆H = -80.64kJ mol-1

a) Using data above, calculate the change in temperature occur during the experiment [Specific heat capacity 4.2 J g-1 o C-1 , density of solution , 1g cm-3 ]

……………………………………………………………………………………..

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b) Write ionic equation …………………………………………………………………………………..

c) Experiments are repeated with the following changes. What is the effect on change in temperature? Explain your answer

concentration of copper(II) sulphate solution is doubled, without changing the volume

…………………………………………………………………………………………………………………………

The volume of copper(II) sulphate solution is halved without changing the concentration

……………………………………………………………………………………………………….

7) State differences between heat change and heat of reaction

Heat change Heat of reaction

a) Other names Depends on name of reactions1)2)3)4)

b) What formula to use ?

c) Unit?

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d) Symbol?

Draw the following diagrams – form 4 chapters

1 To determine the melting point of naphthalene

2 To determine the freezing point of naphthalene

3 Graph for melting point of naphthalene

4 Graph for melting point of naphthalene

5 Electrolysis of molten lead(II) bromide

6 Electrolysis of sulphuric acid to collect gases formed using carbon electrodes

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7 Electrolysis of silver nitrate solution using silver electrode

8 Electroplating of iron key with silver using electrolysis method

9 Purifying impure copper using electrolysis method

10 To determine the position of metals in the electrochemical series using potential difference

11 Simple cell between magnesium and iron using porous pot

12 Daniell cell using salt bridge

13 Heating of copper(II) carbonate 14 To determine empirical formula of magnesium oxide

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15 To determine empirical formula of copper oxide

16 Arrangement of atoms in alloy bronze

17 To separate insoluble salt from soluble reactants

18 Titration method in reaction between acid and alkali

18 Structure of polythene and structure of its monomer

19 Electron arrangement of compound formed between sodium and chlorine [ given proton number of Na, 11: Cl, 17]

20 Electron arrangement of compound formed between carbon and chlorine [ given proton number of C, 6: Cl, 17]

21 Electron arrangement of compound between magnesium and oxygen [ given proton number of Mg, 12: Cl, O,8]

22 Electron arrangement of compound formed between carbon and oxygen

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[ given proton number of C,6; O, 8]

Draw the following diagrams – form 5 chapters

21 To determine the effect of size of reactant on the rate of reaction between zinc and hydrochloric acid

22 To determine the effect of temperature on the rate of reaction between sodium thiosulphate and hydrochloric acid

23 To compare the reactivity of three different metals with oxygen ( magnesium, zinc and copper)

24 To show transfer of electron at a distance between potassium iodide and chlorine water

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25 Diagram of soap particle showing hydrophobic and hydrophilic part

26 Diagram of detergent particle showing hydrophobic and hydrophilic part

27 Diagram of soap particle showing hydrophobic part dissolve in grease while the hydrophilic part dissolve in water

28 Preparation of soap in the laboratory

29 Energy level diagram showing endothermic reaction

30 Energy level diagram showing exothermic reaction

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31 To determine the heat of combustion of ethanol

32 Diagram on process of rusting of iron

33 Effect of contact of other metals on the rusting of iron

34 Simple Structure of vulcanized rubber

35 Diagram of a rubber particle in a colloidal solution

36 Diagram showing process of coagulation of latex

37 Dehydration of ethanol to form 38 Fermentation of glucose

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ethane

39 Graph of volume of carbon dioxide against time

40 Graph of concentration of sodium thiosulphate against time

41 Graph of temperature of sodium thiosulphate against time

42 Energy level diagram showing activation energy with catalyst and without catalyst, also show the heat of reaction

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Module 3 –Fats and Natural Rubber

Answer the following questions

1) FATS

Oils and fats are esters

I) From diagram above, what is the difference between a fat molecule and a fatty acid molecule?

……………………………………………………………………………………………………………………………

……………………………………………………………………………………………………………………………

……………………………………………………………………………………………………………………………

+ +Carboxylic

acids

Alcohol Fats or oil

water

Fatty acidGlycerol or 1,2,3-propanentriol

Has a very long chain carbon, (about 10-20 atoms)

Examples, palmitic acids, stearic acids, linoleic acids

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a) Can hexanoic acid and pentanol react together to form Fat or Oil? Explain your answer

……………………………………………………………………………………………………………………………

b) Can decanoic acid and glycerol react together to form Fat or Oil? Explain your answer

……………………………………………………………………………………………………………………………

c) State 2 similarities between fats and oils?

……………………………………………………………………………………………………………………………

……………………………………………………………………………………………………………………………

d) Fill in the table below to list differences between oils and fats.

Oils Fats

a) sources

b) Physical state at room temperature

c) Melting point

d) Fill in the table below to list differences between saturated and unsaturated fats

Unsaturated fats Saturated fats

a) Proportion of molecules between saturated and

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unsaturated fats

b) Physical state at room temperature

c) Melting point

d) sources

e) Why do unsaturated fats turn bad or spoil easily?

……………………………………………………………………………………………………………………………………………

f) Explain how unsaturated fats can be changed to saturated fats?

…………………………………………………………………………………………………..

…………………………………………………………………………………………………..

…………………………………………………………………………………………………..

2) Natural rubber

a) List examples of natural polymers and their monomers

polymers monomers

1 Starch

2 Cellulose

3 Protein

4 Rubber

b) Draw the structural formula of natural rubber

………………………………………………………………………………………………………………………..

c) State the properties of natural rubber

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i) White ………………………………… at room temperatureii) Elsticity that …………………………………………… overtimeiii) Softiv) Sensitive to …………………………………..

d) State 3 uses of natural rubberi) …………………………………………………………………………………………

………………………

ii) ………………………………………………………………………………………………………………..

iii) …………………………………………………………………………………………………………………..

COAGULATION OF LATEX -PROCESS

I) Latex is a …………………………………………………………II) It consists of ………………………………………….particles dispersed in

…………………………………III) Each rubber particle is made-up many long-chain

…………………………………………..molecules enclosed by a …………………………..-like membrane which is ……………………………charged

Draw diagram of one rubber particle

DESCRIBE THE COAGULATION OF LATEX

i) The repulsion between the …………………………………………..charged particles prevent the ………………………………..particles from coming close to each other. Therefore latex could not …………………………………………

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Draw diagram

ii) When an ………………………………………is added to latex, OR when latex is exposed to ……………………………….., the …………………………..from the air enters the latex and produce ………………………………………..acid that form ……………………ions. This ……………………………….ions neutralize the …………………………………charges on the protein membrane.

Draw diagram

iii) The rubber ………………………………………..can now come close together. This enable them to ………………………………………….with one another resulting in the ………………….. of the protein membranes.

Draw diagram

iv) The rubber molecules …………………………………… with one another and get …………………………….. and thus causing latex to …………………………….

Draw diagram

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IV) Describe how to prevent the coagulation of latex

By adding …………………………………….solution, that contains ……………………………….ions which ………………………………………. The acid produced by the bacteria . Therefore rubber particles remain …………………………………… charged and the coagulation is ………………….

VULCANISED RUBBER

a) What is meant by vulcanization of rubber?

………………………………………………………………………………………………………………….

b) In industry, how does the vulcanization of rubber is carried out?

By heating latex with ……………………………………….. OR …………………………………………….

c) Describe how sulphur atoms change the properties of rubber In vulcanization , ………………….atoms form cross-………………between

rubber …………………

These cross ……………………………………….prevent rubber …………………………..from sliding too much when …………………………………………..

The rubber molecules return to their ………………………………….. position after being stretched.

d) Draw cross-linkage of sulphur

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e) Compare and contrast the properties of vulcanized and unvulcanised rubber

SimilaritiesBoth are ………………………………………………………………

Both are ……………………………………………………………. Differences

Vulcanised Differences Unvulcanised rubber

Elasticity

Hardness

Tensile strength

Resistance to heat

Effect of organic solvents

a) State one advantage of natural rubber over synthetic rubberOnly natural rubber can take the tremendous ………………………, ……………………. and ………………………………produced during landing and taking off of an ……………………..

1) The chemical formula for tetrachloromethane is CCl4. What is the relative molecular mass of tetrachloromethane?

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[Relative atomic mass: C, 12; Cl, 35.5]

……………………………………………………………………………………………..

2) The following equation shows the reaction between silver nitrate and sodium chloride. AgNO3(aq) + NaCl(aq) → AgCl(s) + NaNO3(aq)

What is the mass of the insoluble salt produced when 50 cm3 1.0 mol dm-3 silver nitrate reacts with 50 cm3 2.0 mol dm-3 sodium chloride? [Realtive atomic mass : N = 14, O = 16, Na = 23, Cl = 35.5, Ag = 108]

………………………………………………………………………………………………………3) Aluminium carbonate decomposes when heated strongly to produce

aluminium oxide and carbon dioxide. Al2(CO3)3 Al2O3 + 3CO2

What is the maximum volume of the gas that can be obtained at room temperature when 23.4 g of aluminium carbonate is heated?

[ Molar mass of Al2(CO3)3 = 234 g mol-1 ; Molar volume of gas at room temperature = 24 dm3 mol-1]

……………………………………………………………………………………..

4)

Pair of metals Potential difference Negative

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Pasangan logam(V)

Beza upaya (V)

terminal

Terminal negatif

R and copper

R dan kuprum0.44 R

S and copper

S dan kuprum1.70 S

T and copper

T dan kuprum0.53 Cu

What is the potential difference for the pair of metal S and T?

…………………………………………………………………………………..

5) In an experiment, 24 g of element X react with 32 g sulphur to form a compound. What is the empirical formula of that compound ? [Relative atomic mass ; X = 6, S = 32 ]

………………………………………………………………………………………………………………

6) A compound contains 2.56g copper and 0.64g oxygen Determine the empirical formula of the compound Q.

……………………………………………………………………………………………………..

7) The empirical formula of compound L is C2H5. Determine its molecular formula given that the relative molecular mass is 58.[Relative atomic mass: C=12; H=1]

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…………………………………………………………………………………………………………

8) The chemical equation for the reaction is:

H2SO4 + 2KOH K2SO4 + 2H2O

What is the volume of 0.1 mol dm-3 sulphuric acid needed to exactly neutralize 20 cm3 0.1 mol dm-3 potassium hydroxide?

…………………………………………………………………………………………………………

9) Distilled water is added to 20.0 cm3 of solution 0.1 mol dm-3 of Z to make 100.0 cm3 of solution.Calculate the new concentration of solution Z.

……………………………………………………………………………………………..

10) The equation represents a neutralization reaction.

2HNO3 + Ba(OH)2 → Ba(NO3)2 + 2H2O

10.0 cm3 of barium hydroxide solution 0.1 mol dm-3 is titrated with nitric acid 0.1 mol dm-3. If the initial reading of the burette is 10.00 cm3, what is the final reading of the burette?

…………………………………………………………………………………………………….11) 25 cm3 of 0.1 mol dm-3 sodium hydroxide solution is required to react

completely with 12.50 cm3 of dilute hydrochloric acid. Calculate the molarity of the dilute hydrochloric acid used.

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………………………………………………………………………………………….

12) Diagram 22 shows the energy level diagram for neutralisation reaction.

What is the amount of heat released when 50 cm3 2 mol dm-3 sulphuric acid reacts with 50 cm3 2 mol dm-3 potassium hydroxide solution?

…………………………………………………………………………………………………………………………………….

13) The reaction between sodium and chlorine forms a compound with a high melting point.. Determine the mass of the compound formed when 2.3 g sodium reacts with excess chlorine.

[Relative atomic mass Na= 23, Cl= 35.5]

……………………………………………………………………………………

14) Calculate the oxidation number of i) Manganese in KMnO4

…………………………………………………………………………………

ii) chromium in Cr2O7 2-- ion.

Reaction path

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………………………………………………………………………………..

15) The following chemical equation shows the reaction between calcium carbonate and hydrochloric acid.

Determine the mass of calcium carbonate needed in the reaction if 480 cm3 of gas is released at room condition.

(The molar volume of gas at room condition: 24 dm3 mol-1,

Relative atomic mass: C = 12 g, O= 16 g, Ca = 40 g)

........................................................................................................................

16) The volume of gas released is recorded in Table 7.1

Time / s

Masa/ s 0 60 120 180 240 300 360

Volume

of gas /

Experiment

0.00 25.90

33.00

37.00

40.50

42.00

42.00

2HCl + CaCO3 CaCl2 + CO2 + H2O

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cm3

Isipadu

gas / cm3

I

Experiment II 0.00

28.00

36.50

41.00

42.00

42.00

42.00

Based on the graph, determine

(i) The average rate of reaction for the whole experiment

(ii) The average rate of reaction for the first 2 minutes

(iii) the rate of reaction at 90 sec for Experiment I. ( how?)

17)

(Relative atomic mass: N=14, O=16, Cu=64,

molar volume of gas at room condition; 24 dm3 mol-1)

2 Cu(NO3)2 2 CuO + 4 NO2 + O2

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(i) Determine the percentage composition by mass of oxygen in copper(II) nitrate.

.................................................................................................................

.............................

ii) If 3.2 g of copper(II) oxide is produced during the heating process, calculate the volume of oxygen gas evolved at room condition.

…………………………………………………………………………………..

18) Diagram 10 shows an energy level diagram.

Energy

Tenaga

Mg + 2 HCl

Mg Cl2 + H2

ΔH = -50.4 kJ mol -1

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Diagram 10.1

Determine the temperature change when 50 cm3 of 1.0 mol dm-3 of hydrochloric acid reacts with excess magnesium. [Specific heat capacity of solution: 4.2 J g-1 o C-1,

…………………………………………………………………………………………………

19)In this experiment, 5 g excess copper is added to 100 cm3 of 0.5 mol dm-3 silver nitrate solution. The heat of displacement in this experiment is -105 kJmol-1. [ Specific heat capacity of the solution is 4.2 Jg-1oC-1 ; the density of

the solution is 1.0 gcm-3 ] (i) Calculate the heat energy released in this experiment.

……………………………………………………………….ii) Calculate the temperature change in this experiment.

…………………………………………………………………………………..20) 50 cm3 of hydrochloric acid neutralize 50 cm3 of sodium hydroxide.

Initial Temperature of HCl is 29.0 o C, Initial temperature of NaOH is 29.5 oC. Highest temperature of the mixture is 36.0 oC. Calculate heat of neutralization [ Specific heat capacity of the solution is 4.2 Jg-1oC-1 ; the density of the solution is 1.0 gcm-3 ]

…………………………………………………………………………………..

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21) 4.6 g of ethanol is needed to heat 500 cm3 of water . Increase in temperature of water is 30 oC

Molar mass of ethanol is 46 gmol-1. Calculate the heat of combustion of ethanol [ Specific heat capacity of the solution is 4.2 Jg-1oC-1 ; the density of the solution is 1.0 gcm-3 ]

…………………………………………………………………………………

22) Diagram 3 shows the energy profile for the reaction between X and Y to produce Z.

i) What is the activation energy of the reaction and the type of reaction? …………………………………..

ii) What is the heat of reaction for this reaction?

………………………………………………….

………………………………………………………………………………………………….

23) Carbon burns in oxygen in a reaction as shown in the equation below.

C(s) + O2(g) CO2 (g) ▲ H = -394 kJ mol-1

What is the mass of carbon that must be burnt completely to produce 78.8 kJ of heat?

…………………………………………………………………………………………………

24)

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Based on the diagram above, i) state the volume of barium chloride solution 0.5 mol dm-3 for reacts

completely with 5 cm3 of potassium chromate(VI) solution

………………………………………………..ii) calculate the number of mole of barium chloride solution is needed to

reacts completely with 1 mole potassium chromate(VI) solution.