Chemistry

?
Percentage composition
AR of element times number of them /Divided By/ MR of compound *Times 100*
1 of 74
Ar
Ar is the relative atomic mass and is normally the top number
2 of 74
Mr
Relative molecular mass, the sum of all Ar of a compound
3 of 74
Isotope relative abundance
Ar = (mass of isotope 1 *times* relative abundance) + (mass of isotope 2 *times* abundance) /divided by/ Sum of abundances
4 of 74
Moles equation
Moles = Mass /Divided by/ Mr
5 of 74
Calculating mass
1. write balanced equation 2. work out moles of known element mass 3. write down ratios (big numbers in equation) 4. Rearrange mole equation to Mass = Moles * Mr
6 of 74
Empirical formula
1. work out % or mass 2. Ar 3. Percentage /Divided by/ Ar 4. Divide by smallest
7 of 74
Percentage Yields
Percentage Yield = Actual Yield /Divided by/ theoretical yield *Times* 100
8 of 74
Separation - Filtration
Involves separating components of a mixture according to size, with small particles going through the filter, which leaves the larger particles
9 of 74
Separation - Evaporation
Separates mixtures of solids and liquids by evaporating the liquid. Mixture is heated so liquid evaporates leaving the solid
10 of 74
Separation - Distillation
Used to separate liquids that have different boiling points. When one reaches its boiling point it will evaporate and then be condensed, separating the two
11 of 74
Separation - Chromatography
Separates substances according to their solubility in a particular solvent
12 of 74
Atomic Number
Number of protons in nucleus
13 of 74
Mass number
Total of protons + neutrons
14 of 74
Group Number
Indicates the number of electrons in the outer shell
15 of 74
Period Number
How many shells
16 of 74
Group 1 - Lithium
Soft, silvery metal. Lightest metal, least reactive alkali metal but still has to be stored in oil
17 of 74
Group 1 - Sodium
Silvery white metal, not found in nature because of reactivity. Stored in mineral oil to prevent it reacting with air
18 of 74
Group 1 - Potassium
Silvery grey metal, has to be stored in oil, but can sometimes react with oxygen that dissolves in the oil
19 of 74
Group 1 - Rubidium
Silvery metal, very reactive. If it has contact with air it bursts into flames
20 of 74
Group 1 - Caesium
Explodes violently on contact with water and can only be handled in a inert atmosphere
21 of 74
Group 1 - Francium
Highly reactive, radioactive and unstable. Only 30g on earth at a time
22 of 74
Group 1 - Properties (Alkali metals)
React with oxygen to form oxides, react with water to form hydroxides and hydrogen, react with chlorine and bromine to form Bromide and chloride. Get more reactive down the group
23 of 74
Group 1 - Flame test
Lithium - Red, Sodium - Yellow, Potassium - Lilac, Calcium - Brick Red, Barium - Apple Green
24 of 74
Group 7 - Flourine
Pale yellow gas. Highly toxic and explosive. Despite this very small quantities are needed by the human body (fluorides)
25 of 74
Group 7 - Chlorine
Greenish - yellow gas, reactive and toxic, used to disinfect water and clean swimming pools
26 of 74
Group 7 - Bromine
Reddish - brown liquid at room temp, is reactive and toxic
27 of 74
Group 7 - Iodine
Found in its toxic form in salts, essential in human body
28 of 74
Group 7 - Astatine
One of the rarest elements on earth, highly radioactive and breaks down too quickly to be observed
29 of 74
Group 7 - Properties (Halogens)
Increase reactivity up the group
30 of 74
Group 7 - Iron wool test
Chlorine - Iron glows brightly and a blackish - brown deposit is formed, Bromine - Iron glows slightly and brown residue is left, Iodine - Needs strong heating for a reaction
31 of 74
Group 7 - Tests for Halogens
Silver nitrate test - White, chloride - Pale Yellow, bromine - Yellow was iodine
32 of 74
Reactivity of alkali metals and halogens explained
Group 1 only have one electron in the outer shell and group 7 have seven. This means that for group 1 it is easier to lose one than gain seven, and for group 7 it is easier to gain one than lose seven
33 of 74
Group 0 - Noble Gases
Helium, Neon and Argon. Very unreactive
34 of 74
Whats in water
Ions, mainly magnesium, calcium and chloride, microorganisms and pollutants
35 of 74
Ways to save water
Having quick showers, re-use water for plants, don't leave water running and ensure dishwasher/washing machines are full before use
36 of 74
Abstracting water
Obtaining water for human use, e.g. dams/reservoirs, underground pumps, desalination and collecting rain water
37 of 74
Public water supply/treatment
Water from natural sources goes to a reservoir to be stored and allow solids to settle. Filtration removes small particles, chlorination kills bacteria, the water is stored in a tank or water tower and then goes out for public use
38 of 74
Stages of treatment of water - Sedimentation
Larger insoluble particles are removed by allowing them to settle on the bottom of a tank
39 of 74
Stages of treatment of water - Filtration
Smaller insoluble particles are removed by passing through a water filter
40 of 74
Stages of treatment of water - Chlorination
Chlorine is added. It is poisonous to many bacteria and kills them.
41 of 74
Fluoridation - Process
Fluoride is added to drinking water to prevent tooth decay. This can happen naturally, through picking up magnesium and calcium ions through rocks or can be added by hand
42 of 74
Fluoridation - Advantages
In children fluoride helps make the enamel more resistant, fluoride reduces the ability of plaque bacteria to form acid
43 of 74
Fluoridation - Disadvantages
If teeth are exposed to high levels of fluoride then dental fluorosis can occur (white blotches on enamel), fluoridation could be rendered useless as 90% of toothpastes have fluoride in them
44 of 74
Desalination – Process
Desalination is the process of removing salt from water, usually to make it drinkable. It is called reverse osmosis. The sea water is pushed through a filter at high pressure to remove the salt.
45 of 74
Desalination – Disadvantages
Uses a lot of energy, to produce the high pressure needed, costs more than other processes, very expensive because of the energy required, many countries can not afford it, and some do not have a coastline
46 of 74
Desalination – Advantages
Easy to transport as next to sea, can make huge quantities safe to drink, renewable
47 of 74
Distillation
Separating two liquids, by using the different boiling points. Once the liquid with the lower boiling point has evaporated and becomes vapour, goes into the condenser which turns it back into liquid
48 of 74
Solubility curves
How much of a solute dissolves in a solvent. The graph shows this out of g/100g solvent (usually water)
49 of 74
Hard and soft water
Water can be 'hard' or 'soft' depending on where it is from and if it has dissolved calcium and magnesium ions in it
50 of 74
Temporary hard water
Contains calcium hydrogencarbonate and/or magnesium hydrgencarbonate. When the water is boiled the hardness is removed with the formation of solid calcium carbonate
51 of 74
Temporary hard water - Boiled equation
Ca(HCO3) --> CaCO3 + H2O + CO2
52 of 74
Permanent hard water
Boiling does nor soften. Contains chlorides and/or sulphates of calcium and magnesium
53 of 74
Softening hard water - Boiling
Boiling, used for temporary hard water, easy and cheap, however it produces limescale, only practical for small quantities and only works on temporary hard water
54 of 74
Softening hard water - Adding sodium carbonate
Adding sodium carbonate, used for both types of hard water, its cheap, however it produces limescale, only practical for small quantities
55 of 74
Softening hard water - Ion exchange
Ion exchange, used for both types, no limescale is produced and can be used for large quantities. However it is expensive and ions need to be rerplaced
56 of 74
Structure of the earth
Inner core - hottest part of the earth, mostly iron. Outer core - liquid layer, temperatures almost as high as inner core. Mantle - Thickest layer of earth, semi-molten rock. Crust - Thin layer of solid rock
57 of 74
Destructive plate boundary
One plate is subdued under the other to form magma, this forms volcanoes. Oceanic plate is forced under the continental
58 of 74
Constructive plate boundary
Plates move away from each other, magma is released which cools to create rock
59 of 74
Conservative plate boundary
Plates slide past each other. Generating earthquakes. No volcanoes present as no rock melts
60 of 74
Gas in atmosphere
Nitrogen - 78.1%, Oxygen - 20.9%, Argon - 0.9%, Carbon Dioxide - 0.035, Other - 0.065%
61 of 74
Carbon cycle - Photosynthesis
Plants absorb CO2 and produce oxygen
62 of 74
Carbon cycle - Respiration
Animals produce and release CO2
63 of 74
Carbon cycle - Combustion
Some plants and animals do not decay but instead form fossils and have carbon in them. When they are burnt they release CO2
64 of 74
Carbon cycle - Decomposition
Decomposers, e.g. microbes and fungi break down the remains of dead animals and plants releasing CO2 through respiration
65 of 74
Tests for gasses in the air
Oxygen -Glowing splint will re-light, Carbon Dioxide - Bubble through water, lime water will turn cloudy, Hydrogen - Lighting a splint, makes a squeaky pop sound
66 of 74
Acid Rain - Sulphur equation
Sulphur Dioxide + Water --> Sulphurous acid / SO2 + H2O --> H2SO3
67 of 74
Acid Rain - Nitrogen equation
Nitrous oxides + Water --> Nitric acid / NO2 + H2O --> HNO3
68 of 74
Acid Rain
Burning fossil fuels causes acid rain as it releases Sulphur dioxide and Nitrous oxides into the atmosphere, which react with water to form acid rain
69 of 74
Measuring the rate of a reaction
The rate of reaction means how much product (usually mass or volume) is produced in a set time (usually per second)
70 of 74
Explanation of rate of reaction
A chemical reaction occurs when particles collide with on another. The collision needs energy to work. Lots of particles move at high speeds and lots of collisions happen, however only a small amount are successful.
71 of 74
Factors affecting rate of reaction - Temperature
Higher temp = higher rate of reaction. Higher temperature means that the particles move quicker, faster particles mean more energy for each collision and a higher collision frequency means higher reaction rate
72 of 74
Factors affecting rate of reaction - Concentration of Reactants
Increasing concentration increases the number of particles, in the same volume. More particles per unit means there will be more collisions and higher collision frequency means higher rate of reaction
73 of 74
Factors affecting rate of reaction - Surface area
Increasing surface area allows more reactants to collide with each other with enough energy, and more collisions cause a higher collision frequency, so higher rate of reaction
74 of 74

Other cards in this set

Card 2

Front

Ar

Back

Ar is the relative atomic mass and is normally the top number

Card 3

Front

Mr

Back

Preview of the front of card 3

Card 4

Front

Isotope relative abundance

Back

Preview of the front of card 4

Card 5

Front

Moles equation

Back

Preview of the front of card 5
View more cards

Comments

No comments have yet been made

Similar Chemistry resources:

See all Chemistry resources »See all ALL resources »