chemical analysis, assessing purity and separating mixtures, flame tests Flashcards

Question

what is anhydrous copper (ll) sulfate

Answer 1

it is a white solid which doesn't contain any water of crystallisation if added to water it will turn from white to blue and if it was heated with the water it will turn from blue back to white

Answer 2

This method works by pouring a mixture of an insoluble solid and a liquid (which could itself be a solution through filter paper in a filter funnel. The solid, called the residue, is caught in the filter paper. The liquid called the filtrate, passes through the filter paper and is collected as it drips out of the spout of the funnel.

Answer 3

This method works by boiling off a liquid from a solution which contains a solid (called a solute) dissolved in a liquid (called a solvent) which is often water. This is done in an evaporating basin to leave a solid (called the residue). Better crystals can be obtained by heating the solution gently until only half of its original volume remains. The concentrated solution is then allowed to cool and crystallise. If some solution remains, then further filtration can be used to obtain the crystals of solute which then be dried between two sheets of filter paper.

Answer 4

This method is used to obtain a solvent from a solution. The liquid is boiled off in a flask and then its vapour is cooled by using a Liebig condenser so that it condenses back to a liquid. The collected liquid is called the distillate, Simple distillation can also be used to separate two miscible liquids whose boiling points are far apart.

Answer 5

This method works by separating a mixture of two or more miscible liquids whose boiling points are quite close together. It is similar to simple distillation except that a special tube called a fractionating column is placed between the flask and the condenser. As the liquid is heated, the liquid with the lowest boiling point boils off first. This is then condensed and collected as a pure liquid. After the first liquid has been collected the second liquid may be distilled over and so on. The different distillates are known as fractions.

Answer 6

If two Liquids do not mix, they are said to be immiscible eg oil and water. The separation of two immiscible liquids is very simple. The mixture is placed in a separating funnel where the less dense liquid will form the upper layer. The two liquids can then be run out of the funnel one after the other.

Answer 7

Paper chromatography is the simplest type of chromatography. It works by separating a mixture of different soluble substances (usually with different colours). A spot of the mixture is placed on some chromatography paper (stationary phase) which is then dipped into a solvent (mobile phase). As the solvent passes up the paper, the mixture separates aut as different spots as each substance in the mixture moves at a different rate up the paper. The components separate because some are more attracted to the paper whilst others are more attracted to the solvent. Those that prefer to dissolve in the solvent move faster and travel further up the paper.

Answer 8

blue-green

Answer 9

pick one between yellow or orange

chemical analysis, assessing purity and separating mixtures, flame tests Flashcards

(36 cards)