Chemistry revision form 5=form 5 topics

Chemistry Revision Form 5 on topics:consumer, rate of reaction, carbon

compound and thermo chemistry

STRUCTURE OF SOAP PARTICLE

•the organic part •the ionic part

•the hydrophobic part

•the hydrophilic part

• the head part•the tail part

d)Compare and contrast the cleansing action of soap and detergents

Property Soap Detergent 1 sources Made from

………………

or ………………

Made from petroleum fractions

animal

plant

Property

Soap Detergent

2 Molecular

structure

R – COO – Na +

Where R is

……………

R SO3 – or

Alkyl group

Property

Soap Detergent

3 Effectiveness in

hard water

Forms

…………………with hard

water

Does not

form scum with hard water

SCUM

Property

Soap Detergent

4 Effectiveness

in acidic water

Forms

……………. with acidic

water

Does not

form precipit

ate with

acidic water

INSOLUBLE FATTY ACID

Property Soap Detergent

5 Cleaning power

Less powerfu

l…………… powerful

MORE

Property Soap Detergent

6 Effect to the environment

Biodegradable and

do not cause any

……………

Some detergents are non biodegradable and kill aquatic lives

POLLUTION

What does hard water contains?

•Hard water contains calcium ion, Ca2+ or magnesium ion, Mg2+.

Food additivesDYES PRESERVATIVES

FLAVOURING AGENTS

ANTI OXIDANTS

STABILIZERS AND THICKENING

TYPES OF FOOD ADDITIVES AND EXAMPLES

EXAMPLES TYPE1) AZO COMPOUNDS

2) SODIUM NITRITE, SODIUM BENZOATE

DYES

PRESERVATIVES

EXAMPLES TYPE3) MONO SODIUM GLUTAMATE (MSG)4) ASCORBIC ACID(VITAMIN C)

5) ACACIA GUM

FLAVOURING AGENTS

ANTIOXIDANTS

STABILIZERS & THICKENING AGENTS

TRADITIONAL MEDICINES

Modern medicine

1. ANALGESICS

2. ANTIBIOTICS

3. PSYCHOTHERAPEUTIC MEDICINES

Relieves pain without affecting onsciousness

Kill or inhibit growth of infectious bacteria

Control symptoms of mental illness

Modern medicine

1. ANALGESICS

2. ANTIBIOTICS

3. PSYCHOTHERAPEUTIC MEDICINES

Aspirin, codeine paracetamol

penicillin

Stimulant ANTIDEPRESSANTANTIPSYCHOTIC –

REVISION QUESTIONS

SAPONIFICATION

ESTER

TO PRECIPITATE SOAP PRODUCED

POTASSIUM HYDROXIDE

Water that contains Ca2+ or Mg2+

Soap react with Ca2+ or Mg2+ to form scumDetergent does not form scum in hard water.

Inhibit growth of microorganisms

Antioxidants

burning sensations in the back, neck, chest; paralysis; numbness in the same areas; tingling or warmth in the face, arms or back; nausea; facial tightness; rapid heartbeat; chest pains, asthma attacks; drowsiness or cravings for other foods.

-Factors that influence rate of reaction

•Size of substance or its Total surface area•Temperature of reactant solution•Concentration of the reactant solution•catalyst

-collision theory •Before a reaction happens particles must first collide•This is to overcome bonds between particles and to form new bonds•But simple collision does not break bonds•Only effective collision or collision with CORRECT ORIENTATIONS and enough energy to overcome activation energy is able to form products

Activation energy • Is the minimum energy needed for the

colliding particles to form new products• The energy needed is also to overcome

bonds between particles and to form new bonds

• For every reaction , the activation energy is fixed

• Only catalyst can provide alternative path which has a lower activation energy

a) Graph 9 shows the results of Experiment I and Experiment II to investigate the factor of catalyst in the reaction of zinc and hydrochloric acid.

Volume of hydrogen gas (cm3)

Time(s)

Experiment II

Experiment I

(i) Which experiment used catalyst? State the name of the catalyst used. [ 2 marks]

• Experiment I

• Catalyst used :

Copper(II) sulphate solution

• (ii) The reaction between zinc and hydrochloric acid releases energy. Draw an energy profile diagram for both reactions in Experiment I and Experiment II.

• Label Ea for the activation energy without a catalyst andE’a for the activation energy with a catalyst.

•

[4marks]

(iii) Explain the difference in the rate of reaction between Exp I and Exp II based on the collision theory. [4marks] • Rate of reaction Experiment I is higher

than experiment II.• The presence of catalyst in exp 1 will

provide an alternative path with lower activation energy• More colliding particles are able to

overcome the lower activation energy• Frequency of effective collision increase

and so rate of reaction also increase

• (a) Diagram 10 show the energy level of Reaction I and Reaction II.

• Based on Diagram 10, compare the energy level diagram between Reaction I and Reaction II.

•

Energy

N2 (g)+ 2O2(g)

2NO2 (g)

H = +66 kJ mol-1

Energy

KCl + AgNO3

AgCl + KNO3

Reaction IReaction II

• Reaction I is an endothermic reaction while reaction II is an exothermic reaction.• In reaction 1, Heat energy is absorbedIn reaction II, heat energy is released

• In reaction I, energy of reactants is lower than the energy of products while In reaction II, energy of reactants is higher than the energy of products

b) Table 10 shows the molecular formula and the heat of combustion for propanol and butanol.

AlcoholMolecular

FormulaHeat of combustion/ kJ mol-1

Propanol C3H7OH -2100

Butanol C4H9 OH -2877

Based on the information in Table 10, compare the heat of combustion betweenpropanol and butanol. Explain why there is a difference in the values of the heat of combustion between propanol and butanol.

[3 marks]

• Heat of combustion for butanol is higher than in propanol.• Because the number of carbon atom

and hydrogen atoms per molecule in butanol is higher than in propanol.• So, more heat energy is released to

form carbon dioxide and water in butanol than heat released in propanol

5) Carbon compound

Diagram shows the structural formula of two organic compounds

K and L.

Compound K Compound L

Compound K and L belong to two different homologous series.

(a) Write the general formula for the homologous series of compound K.

CnH2n+1COOH(b) Name compound L.

methyl propanoate

(c) Compare two physical properties of compounds K and L by completing the following table:

Physical property

Compound K Compound L

odour

Solubility soluble in water

Sharp smell Sweet and Fruity smell

Not soluble inwater

6) Thermo chemistry example of paper 3

Plan a laboratory experiment to investigate the relationship between the molar mass of alcohols on the heat of combustion of alcohols. Your planning should include the following:

(a) Statement of problems

Does an alcohol with a higher molar mass have a higher heat of combustion of alcohols?

What is the relationship between the molar mass of alcohols and the heat of combustion of alcohols?

(b) All the variablesManipulated :variable

Responding :VariableConstant :Variables

Different types of Alcohols

Heat of combustion

volume of water, copper can

(c) Statement of hypothesis

The higher the molar mass of alcohol, The higher the heat of combustion of alcohol

(d) List of substances and apparatus

Substances :Methanol, ethanol, propan-1-ol, and butan-1-ol, water

Apparatus :Copper can, measuring cylinder, Thermometer, spirit lamp, Bunsen burner,Tripod stand, wooden block, Wind shield, electronic balance

(e) Procedure of the experiment1. Measure 100cm3 of water using a measuring cylinder. Pour it into a

copper can2. Place the copper can on a tripod stand3. After 3 minutes, measure and record

the initial temperature of water4. Pour 50cm3 of methanol into a spirit

lamp and weigh it5. Place the lamp on wooden block under

the copper can

6.Light up the wick of the lamp immediately

7.Stir the water continuously using a thermometer while observing the increase in temperature

8.Once the temperature has increased to 30oC, put out the flame immediately

9.Record the highest temperature of water

10.Weigh the spirit lamp with methanol again

11.Repeat step 1-10 by using ethanol, propan-1-ol, and butan-1-ol to

replace methanol

(f) Tabulation of dataType of Alcohols Metha

nolEthanol

Initial temp of water (oC)

Highest temp of water(oC)Mass of spirit lamp before combustion(g)Mass of spirit lamp after combustion (g)

(f) Tabulation of dataType of Alcohols propa

nolbutanol

Initial temp of water (oC)

Highest temp of water(oC)Mass of spirit lamp before combustion(g)Mass of spirit lamp after combustion (g)