Chemistry topic 1 Flashcards

Question

What is Filtration?

Answer 1

Can be used if your product is an insoluble solid, which needs to be separated from a mixture, Or it can be used for purification. Simply place some filter paper in pot a funnel, and pour the mixture into a beaker (the residue will be left behind).

Answer 2

1. Pour a solution into an evaporating dish. 2. Slowly heat (the solvent will evaporate and the solution will become gradually more concentrated) 3. Keep heating until you are left with dry crystals.

Answer 3

1. Pour the solution into an evaporating dish and gently heat, solvent will evaporate. 2. Once some crystals start to form, remove from the heat and leave to cool. 3. The salt should start to form crystals as it becomes insoluble in the highly concentrated, cold solution. 4. Filter the crystals and dry with towel or leave.

Answer 4

1. Grind the mixture to ensure the crystals are small and will dissolve more easily. 2. Put the mixture into water and stir, only the salt will dissolve, not the sand. 3. Filter the mixture, the grains of sand will be left as residue. 4. Evaporate the water form the salt so it forms dry crystals.

Answer 5

1. The solution is heated, the part with the lowest boiling point will evaporate first. 2. The Vapour is then cooled, condenses and is collected as a liquid. 3. The rest of the solution is left behind in the flask. You can use simple distillation to separate saltwater, as the water is condensed and you’ll be left with salt. However, the problem with it is the mixture of components have to have very different boiling points…

Answer 6

If you have a mixture of liquids with SIMILAR boiling points eg. Crude oil, then this method will work. 1. Place your mixture in a fractionating column, and heat (the lowest boiling point will evaporate first). 2. When the temp of the thermometer reaches the temp of its boiling point, it will reach the top of the column. 3. Liquids with higher boiling points will start to evaporate, but the column is taller towards the top so they’ll only get part way down before condensing agin. 4. Once the first liquid has been collected, you raise the temp of the Bunsen burner until the next one reaches the top.

Answer 7

1. 19th century, John dalton describes the atom as a solid sphere, and spheres make up other elements. 2. 1897 and Jj Thompson concludes that the atoms weren’t solid spheres but a plum pudding (ball of pos charge, electrons stuck in it). 3. Rutherford uses the alpha particle experiment (fired alpha particles at a sheet of gold, some deflected some passed through), to prove the electron surround the nucleus. 4. Bohr discovered that the electrons must be in a shells, a certain distance from the nucleus. 5. Further experiments concluded that the nucleus contained protons. Then James Chadwick carried out an experiment proving that neutrons existed too!

Answer 8

- The shells closest to the nucleus are always filled first. - atoms are much happier with a full shell, however most atoms don’t have a full outer shell, making them more reactive. - only a certain amount of electrons allowed per shell 1st = 2, 2nd = 8 3rd = 8 4th = 2

Answer 9

- By relative atomic mass + their physical and chemical properties. - the scientists had no idea about atomic structure and could only measure atomic mass.

Answer 10

Dmitri Mendeleev 1869, categorised elements in order of atomic mass, or similar properties. He left gaps to ensure all elects stayed in similar groupings. HOWEVER…………. the discovery of isotopes confirmed that Mendeleev should have considered properties as isotopes of the same element have different chemical properties.

Answer 11

- in order of increasing atomic (proton) number, meaning there are repeating patterns periodically -metals and non metals - the rows are called periods, each representing another full shell of electrons. - elements with similar properties from Columns (groups).

Answer 12

- metals are elements which can form positive ions when they react. - metallic bonding (which causes them to have similar physical properties). - strong, malleable, good conductors, high melting and boiling points.

Answer 13

- don’t form positive ions - tend to look dull - brittle, low density and don’t conduct

Answer 14

Atoms generally react to form a full outer shell, they do this by losing or gaining electrons. - Metals to the left of the periodic table don’t have many electrons to remove, and metals to the bottom have electrons which are a long way from the nucleus so weaker attraction, meaning it’s easy to form positive ions. - non metals to right if the table have lots of electrons, and non metals towards the top have a electrons with a strong attraction, so it’s hard for them to share or gain electrons.

Answer 15

- alkali metals lithium, sodium etc… - one electron in their outer shell increases reactivity -soft, low density. - going down the group, the reactivity increase, lower boiling/melting points, and higher atomic mass. - form ionic compounds with non metals. - produces hydrogen gas when reacting with water. - reaction with chlorine produces a salt. - react with oxygen to form oxide/ peroxide/ superoxide.

Answer 16

- all non metals, with coloured vapours, Fluorine (yellow gas), chlorine (green gas), Bromine (red brown volatile liquid), iodine (purple vapour). - become less reactive down the group, higher boils/melting points and higher atomic masses. - all have 7 electrons in the outer shell. - form molecular compounds (covalent bonding) - form ionic bond with metals - more reactive halogens will displace less reactive ones

Answer 17

- all colourless gases (don’t react) - boiling points will increase due to an increased number of electrons. -they are unreactive as they all have full outer shells of electrons. -includes neon, helium, argon etc…

Chemistry topic 1 Flashcards

(42 cards)