C5-Chemical Changes
- Created by: Aidan Bradley
- Created on: 26-10-17 12:32
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- C5-Chemical changes
- C5.7-Neutralisation & the PH scale
- Acids are substances that produce positive hydrogen ions when you add them to water
- Bases are substances that will neutralise acids
- 5.3-extracting metals
- A metal ore contains enough of the metal to make it economic to extract the metal. Ores are mined and might need to be concentrated before the metal is extracted and purified
- Gold and some other unreactive metals can be found in their native state
- The reactivity series helps you decide the best way to extract metals from their ores. The oxides of metals below carbon in the series can be reduced by carbon to give the metal element
- Metals more reactive than carbon cannot be extracted from their ores using carbon. They are extracted by electrolysis of the molten metal compound
- C5.6-Making more salts
- An indicator is needed when a soluble salt is prepared by reacting an alkali with an acid
- The titration can be repeated without the indicator to make a salt, then a pure, dry sample of its crystals prepared
- A carbonate reacts with an acid to produce a salt, water and carbon dioxide
- 5.2-Displacement reactions
- A more reactive metal will displace a less reactive metal from its aqueous solution
- The non-metals hydrogen and carbon can be given positions in the reactivity series on the basis of displacement reactions
- Oxidation is the loss of electrons
- OILRIG
- Reduction is the gain of electrons
- OILRIG
- C5.8-Strong and weak acids
- Aqueous solutions of weak acids, such as carboxylic acids, have a higher pH value than solutions of strong acids with the same concentration
- As the pH decreases by 1 unit, the hydrogen ion concentration of he solution increases by a factor of 10
- C5.4-Salts from metals
- A salt is a compound formed when the hydrogen in an acid is holly or partially replaces any metal or ammonium ions
- Salts can be made by reacting a suitable metal with an acid. The metal must be above hydrogen in the reactivity series but not dangerously reactive
- The reaction between a metal and an acid produces hydrogen gas as well as a salt. A sample of the salt made can then be crystallised out of solution by evaporating off the water
- C5.5-Salts from insoluble bases
- when an acid reacts with a base, a neutralisation reaction occurs
- The reaction between an acid and a base produces a salt and water
- The sum of the charges on the ions in a salt add up to zero. this enables you to work out the formula of salts, knowing the charges on the ions present
- A pure dry sample of the salt made in an acid base reaction can be crystallising out of solution by evaporating off most of the water and drying with filter papers if necessary
- C5.1-the reactivity series
- Potassium(K) Sodium(Na) Lithium (Li) Calcium (Ca) Magnesium Aluminium(Al) Carbon (C) Zinc (Zn) Iron(Fe) Hydrogen (H) Copper (Cu) Silver (Ag) Gold (Au
- C5.7-Neutralisation & the PH scale
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