Chemistry Must Know Facts EDEXCEL IGCSE
What is the mass of a proton? | 1 |
What is the mass of a neutron? | 1 |
What is the mass of an electron? | 1/2000 (or 1/1840) |
What is the charge on a proton? | +1 |
What is the charge on an electron? | -1 |
What is the charge on a neutron? | 0 |
What is the state symbol for something dissolved in water? | (aq) |
What is a covalent bond? | The electrostatic attraction between 2 nuclei and a shared pair of electrons between them |
What types of element do covalent bonds form between? | Two non-metals |
What is an ionic bond? | The electrostatic attraction between 2 oppositely charged ions. |
What types of element do ionic bonds form between? | A non-metal and a metal. |
Give 2 observations when sodium reacts with water. | Solid appears to disappear. |
Give 1 observation that is seen with potassium but not sodium | Gas burns with lilac flame. |
What is the formula of ammonia? | NH3 |
What is the formula and charge of a nitrate ion? | NO3- |
What is the formula and charge of a carbonate ion? | CO32- |
What is the formula and charge of an ammonium ion? | NH4+ |
What is the formula and charge of a zinc ion? | Zn2+ |
What is the formula and charge of a silver ion? | Ag+ |
What is the formula and charge of a hydroxide ion? | OH- |
What is the formula and charge of a sulphate ion? | SO42- |
What state is chlorine at room temperature? | gas |
What colour is chlorine at room temperature? | green |
What state is bromine at room temperature? | liquid |
What colour is bromine at room temperature? | brown |
What state is iodine at room temperature? | solid |
What colour is iodine at room temperature? | Grey |
What percentage of air is nitrogen? | 78% |
What percentage of air is oxygen? | 21% |
What percentage of air is argon? | 0.9% |
What percentage of air is carbon dioxide? | 0.04% |
Which 2 main gases dissolve in rain to cause acid rain? | Nitrogen Dioxide and Sulphur Dioxide |
What acid is formed when sulphur dioxide dissolves in rain? | Sulphurous Acid |
What is seen when copper carbonate decomposes? | Green powder (CuCO3) forms black powder (CuO) |
How do I test for Carbon Dioxide and what result would I get? | Test: Bubble through limewater Result: White ppt |
How do I test for Iron (III) Ions and what result would I get? | Test: Add sodium hydroxide Result: Orange-brown ppt |
How do I test for Water and what result would I get? | Test: Add anhydrous copper sulphate |
How do I test to see if water is pure? | Test: Heat it up |
How do I test for Sulphate Ions and what result would I get? | Test: Add dilute hydrochloric acid then barium chloride |
How do I test for Hydrogen Gas and what result would I get? | Test: Add lit splint |
How do I test for Calcium Ions and what result would I get? | Test: Flame Test |
How do I test for Bromide ions and what result would I get? | Test: Add dilute nitric acid then silver nitrate |
How do I test for Lithium Ions and what result would I get? | Test: Flame Test |
How do I test for Ammonia and what result would I get? | Test: Add damp red litmus paper |
How do I test for Sodium Ions and what result would I get? | Test: Flame Test |
How do I test for Iodide Ions and what result would I get? | Test: Add dilute nitric acid then silver nitrate |
How do I test for Carbonate Ions and what result would I get? | Test: Add nitric acid and bubble gas given off through limewater |
How do I test for Ammonium Ions and what result would I get? | Test: Add sodium hydroxide and test gas given off with damp red litmus paper Result: Turns blue |
How do I test for Chloride Ions and what result would I get? | Test: Add dilute nitric acid then silver nitrate |
How do I test for Oxygen gas? | Test: Add a glowing splint |
How do I test for Chlorine Gas and what result would I get? | Test: Damp blue litmus paper |
How do I test for Iron (II) Ions and what result would I get? | Test: Add NaOH |
How do I test for Copper (II) Ions and what result would I get? | Test: Add NaOH |
Give another test for Copper (II) ions and what result I would get? | Test: Flame Test |
How do I test for Potassium Ions and what result would I get? | Test: Flame Test |
What color is litmus in acidic conditions? | Red |
What color is litmus in alkaline conditions? | Blue |
What color is phenolphthalein in acidic conditions? | Colourless |
What color is phenolphthalein in alkaline conditions? | Pink |
What color is methyl orange in acidic conditions? | Red |
What color is methyl orange in alkaline conditions? | Yellow |
Give the 6 solubility rules. | Nitrates - Soluble Carbonates - All insouble apart from group 1 and ammonium compounds |
Group 1 compounds and ammonium salts? | All soluble |
Nitrates? | All soluble |
Chlorides? | All soluble except silver chloride and lead (II) chloride. |
Sulphates? | All soluble except barium sulphate, lead (II) sulphate, and calcium sulphate. |
Carbonates? | All insoluble apart from group 1 and ammonium compounds. |
Hydroxides? | All insoluble apart from group 1, ammonium, and calcium. |
What is an ore? | A natural material from which a metal or valuable mineral can be profitably extracted. |
What 2 things does iron need to rust? | Water, oxygen |
Give 3 ways of preventing iron from rusting. | Sacrificial protection, painting, galvanising, oiling, greaseing etc. |
Name the 6 main fractions of crude oil from smallest to largest. | Refinery gases, gasoline, kerosene, diesel, fuel oil and bitumen |
Give a use of the refinery gases fraction. | Heating homes & cooking. |
Give a use of the gasoline fraction. | Petrol for cars. |
Give a use of the kerosene fraction. | Jet fuel. |
Give a use of the diesel fraction. | Fuel for cars and trucks. |
Give a use of the fuel oil fraction. | Fuel for ships and heating. |
Give a use of the bitumen fraction. | Tar for roads. |
What temperature is required for catalytic cracking? | 600 - 700oC |
What catalyst is required for catalytic cracking? | Silicon dioxide or aluminium oxide |
Give the names of the 6 smallest alkanes starting with the smallest. | Methane, Ethane, Propane, Butane, Pentane, Hexane |
Give the general formula for the alkanes | CnH2n+2 |
Name the products of complete combustion. | Water and Carbon Dioxide |
Name the products of incomplete combustion. | Water, Carbon Monoxide (and possibly some carbon as soot) |
Give the general formula for the alkenes | CnH2n |
What catalyst is used to produce ethanol from ethene and steam? | Phosphoric Acid |
What temperature is used to produce ethanol from ethene and steam? | 300oC |
What pressure is used to produce ethanol from ethene and steam? | 60-70 atm |
What temperature is used to produce ethanol from the fermentation of sugars? | 30oC |
How can be ethanol be converted to ethanoic acid? | Add potassium dichromate and dilute sulphuric acid then heat |
What is seen when potassium dichromate reacts with an alcohol | Orange potassium dichromate turns green |
How is ethanol naturally converted to ethanoic acid? | Microbes in the air react it with oxygen. |
How can a carboxylic acid and an alcohol be converted to an ester? | Heat with a sulphuric acid catalyst |
Give two uses of esters. | Food flavourings and perfumes. |
Give 3 uses of polymers. | Making plastic bags, window frames, furniture etc. |
Give 2 environmental problems with polymers. | They are inert so don't biodegrade and produce toxic gases when burned. |
What is seen when sulphur burns - Blue flames and fumes of sulphur dioxide gas
What is seen when magnesium burns - White flame and white magnesium oxide powder.