Course

O Level Chemistry: Practical Skills and Analysis (5070)

Name: O Level Chemistry: Practical Skills and Analysis (5070)
Price: 999 BDT

5070 topic 12 and the Paper 3 or Paper 4 skills, taught step by step: apparatus, planning, tables and graphs, titration, chromatography, separation, and tests for ions and gases.

55 lessons9h 6mEnglish

What you'll learn

Choose the right apparatus for a measurement and read its scale to the right precision
Plan a fair test, record results in a table with units, draw a graph and evaluate the method
Carry out a titration in the right order, find the end-point and calculate a concentration from concordant titres
Run and read a chromatogram and calculate an Rf value
Choose and explain a separation method, and judge purity from melting and boiling points
Identify gases, cations and anions from the Notes for use in qualitative analysis, and name an unknown salt

Requirements

Particles, formulae and the mole from Matter, Bonding and the Mole
Acids, bases and salts from Reactions and the Periodic Table, for chapters 2 and 5
A calculator, a ruler and graph paper

Course content

55 lessons · 9h 6m

12.1 · Experimental design

Choose and read measuring apparatus, use the words for solutions, plan a fair test, record results in a table and a graph, and evaluate a method.

0/13

Measuring time, temperature and mass

Stop-watch, thermometer and balance: what each measures, its unit and how finely it reads.

Preview10m 2.

Measuring volume

Measuring cylinder, volumetric pipette, burette and gas syringe: pick the one the job needs.

Preview11m

Reading scales accurately

Read at eye level, to the bottom of the meniscus, and to the nearest half division.

11m

Solvent, solute, solution and saturated solution

Sugar dissolves in tea: the words for what dissolves, what it dissolves in and when no more will.

10m

Variables and fair tests

Change one thing, measure one thing, keep everything else the same.

11m

Planning an investigation

Range, number of values, repeats, apparatus and safety: write a plan another student could follow.

12m

Advantages and disadvantages of methods and apparatus

A gas syringe or an upturned cylinder? Say what each method gains and what it loses.

11m

Recording results in a table

Units in the headings, readings to the precision of the instrument, one column for each quantity.

11m

Drawing and using graphs

Choose a scale, plot with crosses, draw a best-fit line, then read values from it.

12m

10.

Errors, anomalous results and improvements

Spot the result that does not fit, find the source of error, and suggest a real improvement.

12m

11.

Experimental design: practice

A timed drill of mixed cards, then mixed questions with full working.

12.

Experimental design: exam practice

Exam-style questions with marks, mark schemes and full worked solutions.

15m

13.

Experimental design: summary

The key points, equations and common mistakes on one screen, with cards to revise from.

12.2 · Acid-base titrations

Use a volumetric pipette, a burette and an indicator to carry out a titration, find the end-point, record concordant titres and use them in a calculation.

0/8

The burette and the volumetric pipette

The pipette delivers one exact volume; the burette measures any volume you add.

Preview11m 2.

Carrying out a titration

Rinse, fill, pipette, add indicator, run in, swirl, stop at the colour change. Every step has a reason.

Preview12m

Indicators and the end-point

The end-point is the first permanent colour change. Methyl orange and phenolphthalein show it.

11m

Recording titration results

Readings to 0.05 cm³, a rough run, then concordant titres within 0.10 cm³ and their mean.

11m

Calculating a concentration from titration results

Moles from the burette, the mole ratio, then concentration in the flask.

12m

Acid-base titrations: practice

A timed drill of mixed cards, then mixed questions with full working.

Acid-base titrations: exam practice

Exam-style questions with marks, mark schemes and full worked solutions.

15m

Acid-base titrations: summary

The key points, equations and common mistakes on one screen, with cards to revise from.

12.3 · Chromatography

Run a paper chromatogram, read it to identify substances and judge purity, use a locating agent for colourless spots, and calculate Rf values.

0/7

Paper chromatography

A pencil line, small spots, a solvent below the line and a lid: the colours in ink separate as the solvent rises.

Preview11m 2.

Interpreting chromatograms

Match spots to known substances; one spot means pure, more than one means a mixture.

Preview11m

Rf values

Rf is the distance the spot moved divided by the distance the solvent moved. It is always less than 1.

12m

Locating agents

Colourless spots are invisible until a locating agent is sprayed on and makes them show.

10m

Chromatography: practice

A timed drill of mixed cards, then mixed questions with full working.

Chromatography: exam practice

Exam-style questions with marks, mark schemes and full worked solutions.

15m

Chromatography: summary

The key points, equations and common mistakes on one screen, with cards to revise from.

12.1, 12.4 · Separation and purification

Separate mixtures with a solvent, filtration, crystallisation, simple and fractional distillation, choose a method from the substances given, and use melting and boiling points to judge purity.

0/10

Using a suitable solvent

Choose a solvent that dissolves one substance and not the other, as water does for salt and sand.

Preview10m 2.

Filtration

The filter paper keeps the solid (the residue) and lets the liquid (the filtrate) through.

Preview11m

Crystallisation

Heat to the point of crystallisation, then cool slowly: crystals grow from a saturated solution.

11m

Simple distillation

Boil the solvent off, cool it back to a liquid in a condenser, and collect it pure.

11m

Fractional distillation

A fractionating column separates liquids whose boiling points are close together.

12m

Choosing a separation method

Solid or liquid? Dissolved or not? Close boiling points? Three questions pick the method.

12m

Melting point, boiling point and purity

A pure substance melts and boils at one sharp temperature; an impure one over a range.

11m

Separation and purification: practice

A timed drill of mixed cards, then mixed questions with full working.

Separation and purification: exam practice

Exam-style questions with marks, mark schemes and full worked solutions.

15m

10.

Separation and purification: summary

The key points, equations and common mistakes on one screen, with cards to revise from.

12.5 · Identification of ions and gases

Test for six gases, use flame tests and sodium hydroxide or ammonia to identify cations, test for six anions, and put the tests together to name an unknown salt.

0/12

Tests for hydrogen, oxygen and carbon dioxide

A lighted splint pops, a glowing splint relights, limewater turns milky.

Preview11m 2.

Tests for ammonia, chlorine and sulfur dioxide

Damp red litmus turns blue, damp litmus is bleached, purple manganate(VII) turns colourless.

Preview11m

Flame tests

Lithium red, sodium yellow, potassium lilac, calcium orange-red, barium light green, copper blue-green.

11m

Testing cations with aqueous sodium hydroxide

Add a few drops, then excess: the colour of the precipitate and whether it dissolves name the ion.

12m

Testing cations with aqueous ammonia

Ammonia tells apart the ions sodium hydroxide cannot: zinc from aluminium, and copper by its dark blue.

12m

Tests for carbonate, sulfate and sulfite ions

Acid then limewater for carbonate; barium nitrate for sulfate; manganate(VII) for sulfite.

11m

Tests for chloride, bromide and iodide ions

Nitric acid then silver nitrate: white, cream or yellow precipitate.

11m

Test for nitrate ions

Sodium hydroxide and aluminium foil, warm, then damp red litmus: ammonia means nitrate.

10m

Identifying an unknown salt

Test the cation, test the anion, record each observation, then name the salt.

12m

10.

Identification of ions and gases: practice

A timed drill of mixed cards, then mixed questions with full working.

11.

Identification of ions and gases: exam practice

Exam-style questions with marks, mark schemes and full worked solutions.

15m

12.

Identification of ions and gases: summary

The key points, equations and common mistakes on one screen, with cards to revise from.

About the creator

8bitlesson

Cambridge O Level, A Level and university courses, taught through interactive labs.

Mentora builds the sciences and mathematics as things you can move rather than videos you watch. Cambridge O Level and A Level mathematics, physics, chemistry and accounting, a primary mathematics track, and first-year university computer science. Every lesson works a real exam question end to end.