c8 Flashcards

Question

how do you otain the cyrstaks after eveporating the solution

Answer 1

you can filter it out

Answer 2

put your solution into a cocnical flask then because the liquids hav a different boilings points you boil the solution and the soloution with the lowest boiling puoint will come out through the condenser added with cold water the liquid will condense down and will be put intot the beaker

Answer 3

distance moved by the compound / distance moved by the solvent

Answer 4

how soluable a particular substance is in a solvent

Answer 5

n chemistry a pure substance may consist of a single element or compound which contains no other substance.

Answer 6

A mixture consists of two or more elements or compounds that are physically mixed together, they are not chemically combined.

Answer 7

Pure substances melt and boil at specific and sharp temperatures

Answer 8

Mixtures have a range of melting and boiling points as they consist of different substances that melt or boil at different temperatures

Answer 9

This is done using a melting point apparatus which allows you to slowly heat up a small amount of the sample, making it easier to observe the exact melting point. This is then compared to data tables.

Answer 10

Used to separate a liquid and soluble solid from a solution (e.g. water from a solution of salt water) or a pure liquid from a mixture of liquids. The solution is heated and pure water evaporates producing a vapour which rises through the neck of the round-bottomed flask. The vapour passes through the condenser, where it cools and condenses, turning into pure liquid H2O that is collected in a beaker. After all the water is evaporated from the solution, only the solid solute will be left behind.

Answer 11

Used to separate two or more liquids that are miscible with one another (e.g. ethanol and water from a mixture of the two). The solution is heated to the temperature of the substance with the lowest boiling point. This substance will rise and evaporate first, and vapours will pass through a condenser, where they cool and condense, turning into a liquid that will be collected in a beaker. All of the substance is evaporated and collected, leaving behind the other components(s) of the mixture. For water and ethanol: ethanol has a boiling point of 78 ºC and water of 100 ºC. The mixture is heated until it reaches 78 ºC, at which point the ethanol boils and distills out of the mixture and condenses into the beaker. When the temperature starts to increase to 100 ºC heating should be stopped. Water and ethanol are now separated.

Answer 12

his technique is used to separate substances that have different solubilities in a given solvent (e.g. different coloured inks that have been mixed to make black ink). It is also used to identify unknown substances. A pencil line is drawn on chromatography paper and spots of the sample are placed on it. Pencil is used for this as ink would run into the chromatogram along with the samples. The paper is then lowered into the solvent container, making sure that the pencil line sits above the level of the solvent so the samples don ́t wash into the solvent container. The solvent travels up the paper by capillary action, taking some of the coloured substances with it. Different substances have different solubilities so will travel at different rates, causing the substances to spread apart. Those substances with higher solubility will travel further than the others.

Answer 13

filtration sedimentation chlroination

Answer 14

soluble and insouluble impurites and microbes

Answer 15

you pass the mixture adn this leaves insoulble particles on the filter paper as residue

Answer 16

large insoluble particles sink to the bottom of a tank and iron sulfate is sometimes added to help fine particles clump together

Answer 17

to kill of any dead microrganisms

Answer 18

use simple didilation