Chapter C12- Chemical Analysis Flashcards
What is a pure substance?
What two things can a pure substance be?
What two things will a mixture not have whereas a pure substance will?
What two things do impurities do to a substance?
What is the definition of a formulation?
What are formulations designed to give a product?
What are the two types of ingredients?
What is paper chromatography?
In paper chromatography, what does the size of the molecules in each dye affect?
How else can a chemical also be identified?
One that is made up of just one substance
An element or a compound
A sharp melting or boiling point
Lower the melting point and raise the boiling point of a substance
Useful mixtures made up in indefinite proportions
The best properties possible to carry out its functions
Active and inactive ingredients
A technique for separating components of a mixture
The distance travelled up the paper
By its Rf (retention factor).
What is the retention factor of a substance?
In paper chromatography, which is which?
What is the formula for calculating Retention factor (Rf)?
What is the answer for this never greater than?
What are some examples of formulations?
What are the melting and boiling points of an element or compound called?
What does the size of the difference from the fixed point of a pure substance depend on?
What does chromatography involve?
What do these do?
What is an example of these two phases?
Ratio of the distance travelled by the sample to the distance travelled by the solvent
Sample is the spots and the solvent is the water
Distance moved by the sample -:- Distance moved by the solvent
The answer is never greater than 1
Fuels, alloys, fertilisers, pesticides, cosmetics and food products
Its fixed points
The amount of any impurities mixed with it
A mobile phase and a stationary phase
The mobile phase moves through the stationary phase
The mobile phase could be the water and the stationary phase could be the paper.
What test is used to test for hydrogen?
Describe this test?
What test is used to test for carbon dioxide?
What test is used to test for oxygen?
What test is used to test for chlorine and what happens in the test?
What happens in flame tests for metals?
What will each metal produce?
What colours are produced when the following metals are burned:
Iron sulphate (II)
Calcium chloride
Copper chloride
Magnesium
Aluminium sulphate
Potassium chloride
Sodium chloride
Lithian ion
The pop test
Light a splint and put it into a test tube. It will pop if hydrogen is present
Limewater turning milky (cloudy white)
A glowing splint relights
Damp blue litmus paper turns white (as it gets bleached)
The sample of metal is placed in the blue flame on a Bunsen burner
A different coloured flame
Yellow
Orange/red
Green
Colourless
Orange
Lilac
Yellow
Crimson colour.
What does the precipitate reaction for cations involve?
What will be formed in this reaction?
What is the colour of the precipitates formed for the following cations:
Magnesium 2+
Aluminium 3+
Iron 2+
Calcium 2+
Iron 3+
Copper 2+
What is done to distinguish between the white precipitates?
What are the results?
A test with sodium hydroxide solution
A coloured precipitate
White
White
Green
White
Brown
Blue
If you add more sodium hydroxide
The aluminium will dissolve
Calcium and magnesium will not dissolve.
What can sodium hydroxide solution be used to identify?
What is the only way to distinguish between calcium and magnesium cations?
What are examples of three groups of negative ions?
What is the test for carbonates called?
What does it involve?
How do you know if the test is positive for carbonate?
What is the word equation for the test for carbonates?
How could we confirm that the gas produced is carbon dioxide?
What is the test for sulphates called?
What does it involve and why?
How do you know if the test is positive for sulphate?
What compound is formed and how is it described?
Metal ions that form insoluble hydroxides in precipitation reactions
Flame tests
Halide ions (chlorine Cl-, bromine Br-, iodine I-) Carbonate ions (CO3 2-) Sulphate ions (SO4 2-)
The acid test
You add a dilute acid (eg hydrochloric acid)
If it fizzes the test is positive for carbonate
Metal carbonate + Acid— Salt + Carbon Dioxide + Water
If limewater turns milky
The Barium Chloride Test
Adding dilute hydrochloric acid (to remove any carbonate ions) and then adding barium chloride
If a white precipitate is formed the test is positive for sulphate
Barium sulphate which is insoluble.
What is the test for halides called?
What does it involve and why?
How do you know if the test is positive for a halide?
What two things are produced if the test is positive for the following halides:
Chloride
Bromide
Iodide
What two things are important to remember in the test for halides?
What is produced in the test for halides and what would it be classified as?
The silver nitrate test
Adding dilute nitric acid (to remove any carbonate ions) and then adding silver nitrate
If a precipitate is formed
White precipitate of silver chloride
Cream precipitate of silver bromide
Yellow precipitate of silver iodide
No other acid can be used and they all form precipitates
Silver halides which are insoluble.
