Covalent (sharing of electron pairs) Ionic ( electrostatic attraction between oppositely charged ions) Metallic (electrostatic attraction between + metal ions and delocalised electrons)
Group 1 ions 1+ Group 2 ions 2+ Group 3 ions 3+ Group 4 ions 4-/+ Group 5 ions 3-/5+ Group 6 ions 2- Group 7 ions 1- Magnesium chloride Magnesium 2+ Chloride 1- Formula: Magnesium oxide Magnesium 2+ Oxide 2- Formula: Other ions: Ammonium Carbonate Nitrate Sulphate Hydroxide Aluminium oxide: Calcium nitrate: Sodium carbonate: Potassium sulphate: Aluminium sulphate: Aluminium hydroxide: Properties Solids Explanations High melting points and high boiling points Don't conduct as solids Conduct when molten or dissolved
Properties Explanations High melting points and high boiling points Good conductors of heat Good conductors of electricity Properties ( simple covalent) Explanation low melting points and low boiling points Properties ( giant covalent) ExplanationS high melting points and high boiling points Diamond is hard Diamond does not conduct Graphite is slippery & soft Graphite conducts electricity
Nano tubes and fullerenes 1nm= Nano science applications Uses: Pros: Cons:
High density polymer Low density polymer Uses: Uses: Formed from same monomer under different conditions (temperatures, pressures, catalysts) Thermosetting polymer Properties: Thermosoftenig polymer Properties: Explanation: Explanation: Uses: Uses:
Relative formula mass Find the atomic mass of each element in the compound and add up all formula masses. Water: Calcium carbonate: Aluminium hydroxide: Aluminium sulfate: Ammonium carbonate: a mole Each atom has a tiny mass and it is difficult to measure The mass. It is easier to find the mass of many atoms. Scientists have found the mass of 6.023 x1023 many atoms. This number is called 1 mole. The mass of one mole of an atom is equal to the atomic mass in grams. The mass of one mole of a compound is equal to the relative formula mass in grams. 1 mole of water = 1 mole of carbon dioxide = 1 mole of potassium iodide = percentage by mass calculations Example: what is the % by mass of hydrogen in water? There are two hydrogen atoms in water with a total atomic mass of 2. The formula mass of water is 18. The percentage mass of hydrogen is therefore 2/18 x100 = 11% Find the % by mass of oxygen in each compound Calcium carbonate: Aluminium hydroxide: Aluminium sulfate: Ammonium carbonate:
empirical formula the empirical formula is the simplest ratio of elements in a compound. empirical formula & molecular formula Switching between the two using the respective formula masses: finding he empirical formula from % by mass or mass What are the steps?
A compound contains 39.4% by mass of iron and the rest is oxygen. What is the empirical formula? If 1.27gRams of copper made 1.59grams of copper oxide, what is the empirical formula of the copper oxide formed? Reacting mass calculations using the relative formula masses and the idea of moles we can calculate the amounts of products and reactants for a chemical reaction: How much carbon dioxide would be produced from 6 grams of carbon? How much oxygen would you need? How much carbon do you need to produce 169.84 grams of carbon dioxide?
Copper oxide reacts with sulfuric acid to form copper sulphate And water. If 1.59 grams of copper oxide were used, how much copper sulphate is made? Sulphur reacts with oxygen to form sulphur trioxide. If 100 tonnes of sulphur are burnt in a day, how much sulphur trioxide is produced in a week? Percentage yield The student produced 2.2 grams of copper sulphate Instead of 2.8 grams. What is the percentage yield? Percentage yield- why not always 100%? 1. 2. 3. 4. 5.
Hydrated copper sulphate vs dehydrated copper sulphate the forward reaction is endothermic as you need to supply heat to remove the water. water is given off as steam. The backward reaction is exothermic. Some of the water added evaporates as a large amount of heat is released. Definition: Definition: Temperature of surroundings: Temperature of surroundings: Energy profile diagram: Energy profile diagram:
Rate definition: Collision theory: Concentration Surface area Factors that affect the rate of reacionexplanations Temperature Catalyst
How to find the rate experimentally Things to look out for:... the amount of reactant used So... the amount of product made.... amounts of reactants used so... total amount of product made.
Acids are proton...bases are proton... The four types of bases are:... Bases that are soluble in water are called alkalis. Alkalis form oh- ions in solution and tend to be metal hydroxides and ammonia. When acids and bases react, the products can differ: Acid + metal oxide ->... Acid + metal carbonate ->... Acid + metal hydroxide ->... Acid + ammonia ->... Examples:............ Acids react with bases to make salts. Hydrochloric acid makes...salts Sulphuric acid makes...salts Nitric acid makes...salts Ammonia makes...salts Acids react with alkalis to make salt and water. The ionic equation for all acid-alkali reactions is:... Useful salts: Sodium chloride... Epsom salt (Magnesium sulphate)...... Ammonium nitrate...
Salt preparation method Soluble salt Soluble salt Insoluble salt Titration ( acid + alkali) Excess base method (insoluble base + acid) Precipitation method
Electrolysis means 'splitting a compound using electricity'. Draw a labelled diagram to show how you would electrolyse molten lead bromide. Label and define the anode, cathode, anion, cation, electrolyte, oxidation, reduction. Anode half equation (oxidation): Cathode half equation (reduction): When an ionic compound is dissolved in water and the resulting solution is electrolysed, the products at the anode and cathode may differ depending on the position of the ions in the reactivity series.this is because water also consists of ions which are attracted to the anode and cathode. Sodium chloride solution Cations present: Anions present: Cathode reaction: Anode reaction: Copper sulphate solution Cations present: Anions present: Cathode reaction: Anode reaction:
Important electrolysis case studies Electrolysis of brine Electrolyte: Cathode reaction: Anode reaction: Overall equation: Products: Product uses: Diagram: Electrolysis of bauxite Electrolyte: Cathode reaction: Anode reaction: Overall equation: Products: Anode replacement: Role of cryolite: Diagram: Electroplating Electrolyte: Cathode reaction: Anode reaction: Overall equation: Products: Product uses: Copper purification Electrolyte: Cathode reaction: Anode reaction: Overall equation: Products: Product uses: Diagram: Diagram:
Paper chromatography is used to separate colours in inks and dyes. Mobile phase:... Stationary phase:... How to prevent solvent from escaping:... Why to use pencil to draw base line:... How to know which colour dissolved best:... How to set up the experiment. How to interpret the results. gas chromatography is used to separate mixtures of Volatile liquids and gases. Mobile phase:... Stationary phase:... How mixture is separated:... Meaning of retention time:... How to interpret the chromatogram:... The role of the mass spectrometer...