✅Chemistry PAPER2 chemical analysis Flashcards
What is a pure substance
A pure substance is something that only contains one compound or element all the way through and it is not mixed with anything else, it also has melts or boils at a specific temperature
Name a feature of an impure substance
They melt and boil over a range of temperatures
What does pure mean in pure substance
By its self, or an everyday language not mixed
What are two examples of pure substances
Sodium chloride, propane
How can you test how pure a substance is
By measuring its melting or boiling point
What is a formulation
Useful mixtures that have been designed for particular use
What are some examples of formulations
Paint, fertilisers, foods, and medicines
What is chromatography
Chromatography is a method used to separate the substances in a mixture
What are the two phases in paper chromatography
Mobile and stationary
Explain the mobile phase
Where the molecules can move for example in paper chromatography this is a solvent
What happens during paper chromatography
The solvent moves of the paper and carries the substance in the mixture with it
Explain the stationary phase
Where the molecules can’t move for example in paper chromatography this is the paper
What is distribution in paper chromatography
The amount of time a chemical spend is dissolved in a solvent or stuck on the paper
Why is water a suitable solvent in chromatography
Because it is soluble
Describe the chromatography practical
Draw a pencil line across the chromatography paper one 1-2 cm from the bottom, on the line draw two dots with ink, get a container with a suitable solvent in the bottom and then placed the paper in, allow the solvent to move through the paper but remove the paper before the solvent reaches the top
How do you test for hydrogen
Put 5 cm of hydrochloric acid into a tube, add a piece of magnesium ribbon, immediately put a bung inside the tube to seal it, wait for the reaction to happen and you will see bubbles, remove the bung and hold a lit splint above the tube, if the test tube contains hydrogen you will get a squeaky pop
How do you test for oxygen
Stand a test tube containing a small amount of magnesium dioxide into a rack, put about 1 cm of hydrogen peroxide into the test tube and mix it, holds a glowing splint in the neck of the tube and if it relights then it contains oxygen
How do you test for carbon dioxide
Half fill a test tube with lime water and place it in a test tube rack, put a delivery tube into the lime water so the tube is below the surface, add about 5 cm of hydrochloric acid into another test tube and add a small amount of calcium carbonate powder, immediately put the bung into the tube of acid and carbonate and observe the limewater, shake it, if the gas is carbon dioxide the solution will turn cloudy
