Unit 25 & 26 - Qualitative Analysis: Tests For Ions/ Bulk And Surface Properties Of Matter Inclusing Nanoparticles Flashcards
How do you carry out a flame test
Light a Bunsen burner and give it a blue flame
Pick up a small sample using a wire loop
Hold at the edge of the flame and observe the flame colour
What must you do to the wire loop before testing each flame sample
Clean it using hydrochloric acid
What metal might be used as the wire loop and why (2)
Platinum because it’s very unreactive and has a high melting point
Nichrome because it’s cheaper and produces a faint orange colour
What colour does the flame turn with Li+
Red
What colour does the flame turn with Na+
Yellow
What colour does the flame turn with K+
Lilac
What colour does the flame turn with Ca2+
Orange-red
What colour does the flame turn with copper Cu2+
Blue-green
What is a flame photometer
A machine that measures the light intensity of the flame colours
Why is flame photometry better than flame tests? (3)
More sensitive, more accurate, faster
What is a standard solution
A solution containing precisely known measurements of substances
Give a way of treating contaminated water with drains from mines
Using sodium hydroxide solution
What do sodium hydroxide precipitation reactions involve
Adding it to a test to identify dissolved metal ions
When Fe2+ is added to sodium hydroxide, what colour is the precipitate?
Green
When Fe3+ is added to sodium hydroxide, what colour is the precipitate?
Brown
When Cu2+ is added to sodium hydroxide, what colour is the precipitate?
Blue
When Ca2+ is added to sodium hydroxide, what colour is the precipitate?
White
When Al3+ is added to sodium hydroxide, what colour is the precipitate?
White
How can you distinguish calcium ions and aluminium ions if they both form white precipitates?
Aluminium hydroxide disappears to form a colourless solution when excess sodium hydroxide is added but calcium hydroxide doesn’t
What is the tests for ammonia ions
Ammonia changes damp red litmus paper blue
What do rocks with carbonate minerals produce when added to HCl
Bubbles of CO2
What is the tests for carbonate ions
Adding HCl makes CO2
What is the test for sulphate ions
Add HCl to acidity solution and remove carbonate ions, add some barium chloride, if sulphate is present, a white precipitate forms
What is the precipitate formed when barium chloride is added to sulphate ions
Barium sulphate
Which is the only silver halide that is soluble in water
Silver fluoride
How do you detect chloride, bromide and iodide ions?
Add nitric acid to acidity solution and remove carbonate ions, then add silver nitrate which will change the colour
What colour does a solution with chloride ions turn
White
What colour does a solution with bromide ions turn
Cream
What colour does a solution with iodide ions turn
Yellow
Explain the core practical - identifying ions for flame tests for metal cations
Light a Bunsen burner with a blue flame
Pick up a sample using a clean wire loop and hold it over the flame
Record the colour of the flame
Explain the core practical - identifying ions for hydroxide precipitate tests for metal ions
Dissolve a little solid salt in a test tube using distilled water
Add a few drops of dilute sodium hydroxide and record colour of precipitate
If a white precipitate forms, add excess sodium hydroxide and see if it disappears
Explain the core practical - identifying ions for ammonium ions
Dissolve some solid salt
Add some dilute sodium hydroxide and gently warm
Remove from flame and hold stamp red litmus paper near it
Record colour
Explain the core practical - identifying ions for carbonate ions
Put some solid salt in a test tube and add dilute acid
Note down if any bubbling occurs
Use lime water to check if there is CO2
Explain the core practical - identifying ions for sulphate ions
Dissolve some salt using distilled water
Add some dilute hydrochloric acid and add barium chloride solution
See if a white precipitate occurs
Explain the core practical - identifying ions for halide ions
Dissolve some salt in a test tube using distilled water
Add some dilute nitric acid and then some silver nitrate
Record colour of precipitate
What are ceramics
A range of durable compounds that change very little when heated
Give 2 properties of ceramics
Poor electrical conductors, high melting points
What structures are ceramics made from
Giant structures with many strong bonds
Give 2 clay ceramics
Brick, china
How are clay ceramics made
The clay is moulded and heated at a very high temperature which causes tiny crystals to join together
How are bricks made
They are decorated by adding a coloured substance to the clay before heating
How is porcelain and china made to have a waterproof, shiny coating
They are dipped in a glaze and heated strongly again
How is glass made
By melting sand and allowing it to cool and solidify
Why is glass transparent
The crystals are not arranged in a regular way
What is the float process for making modern window glass
Molten glass is poured into a bath of molten tin where is spreads our, the flat layer of glass is drawn away and cooled
Give 2 common properties of polymers
Strong and chemically unreactive
What is rigid PVC used for
Underground pipes and window frames
How can PVC be made softer and flexible
By adding substances called plasticisers
What is flexible PVC used for
Indoor water pipes, waterproof flooring
What is a composite material
A mixture of two or more materials combined to produce an improved material
Give two points about the individual materials in a composite material
Often have contrasting properties
Usually visible in the composite material but can be separated using physical methods
What is pykrete made from
Ice and wood pulp
What is concrete made from
Cement, sand, aggregate and water
What form the reinforcement in cement
Sand and aggregate
What forms the matrix in cement
The reinforcement bonded together by cement
What does high tensile strength mean
Resist to being stretched
What is compressive strength
A measure of how well a material resists to being squashed
Why do concrete beams tend to crack
It is weak in tension
What is concrete reinforced with to make beams
Steel
How is plywood made
Odd numbers of thin sheets of wood glued at right angles
What do nanoparticles consist of
A few hundred atoms
What are nanoparticulate substances
Substances that consist of nanoparticles
Why might titanium dioxide cause cancer
It absorbed harmful ultraviolet radiation from sunlight
Why is nanoparticulate titanium dioxide useful for invisible sun creams
The particles are tiny so it is transparent
Why are nanoparticles good catalysts
They have a large surface area to volume ratio
Why are nanoparticles a risk to human health
They are so small that they can be breathed in
