Chemical Analysis Flashcards
What is the everyday definition of a pure substance?
A substance with nothing added to it such as milk.
What is chemical definition of a pure substance?
A substance containing only one element or compound.
What will impurities do in a sample?
> lower the melting point and increase the melting range.
> increase the boiling point and may also increase the boiling range.
What are formulations?
Useful mixtures with a precise purpose.
What are 5 examples of a formulation?
> metal alloys. > medicines. > fertilisers. > paints. > cleaning products. > food. > cosmetics. > fuels.
What is the test and result for hydrogen?
[use a burning splint held at the open end of a test tube of the gas, burning rapidly with a pop sound]
① 5cm³ acid into a test tube.
② add a small piece of magnesium and quickly place a bung on to collect the gas.
③ have a lit splint ready.
↳ remove bung and burn the gas using the lit splint.
What is the test and result for oxygen?
[use a glowing splint inserted into test tube of the gas resulting in the splint relighting in oxygen]
① 5cm³ hydrogen peroxide into a test tube.
② add a small amount manganese dioxide.
③ light a splint and gently blow or tap so that it’s only glowing.
④ hold the glowing splint in the mouth of the test tube.
What is the test and result for chlorine?
[use a litmus paper and dampen it to put into chlorine gas resulting in the paper bleaching and turning white]
① hold the damp litmus paper over the mouth of the boiling tube/gas.
What is the test and result for carbon dioxide?
[when carbon dioxide is shaken with or bubbled through limewater, the limewater turns milky/cloudy]
① 3cm³ of acid into a boiling tube.
② place 5cm³ of limewater into a test tube.
③ fit the bung and delivery tube.
What is the test and result for carbon dioxide?
[when carbon dioxide is shaken with or bubbled through limewater, the limewater turns milky/cloudy]
① 3cm³ of acid into a boiling tube.
② place 5cm³ of limewater into a test tube.
③ fit the bung and delivery tube.
What is chromatography?
An analytic method used to separate the substances in a mixture. It can be used to identify the substances.
What are the two phases of chromatography?
> stationary phase.
> mobile phase.
What is the stationary phase in chromatography?
Where the molecules can’t move.
What is the mobile phase in chromatography?
Where the molecules can move (the solvent).
What is the practical method of chromatography?
① draw a straight line with pencil on a chromatography paper 1 - 2 cm from the bottom.
② using a pipette/capillary tube to add small spots of each mixture onto the line.
↳ dot up to 3x and leave breaks in between.
③ place the paper into a beaker with the solvent in the bottom below the level of the dots.
④ attach the paper to a glass rod with solar tape the place the paper in the solvent.
⑤ leave it until the solvent has risen near the top of the paper.
⑥ draw a line here the solvent level has reached then measure the distance travelled by each spot and by the solvent.
