GCSE Science-CHEMISTRY worksheet on The EXTRACTION OF METALS

Site Meter * Do online OR printout, do, return to check answers. * GCSE Notes on Metal Extraction * AQA * CCEA * Edexcel * OCR 21stC * OCR Gateway * WJEC * EMAIL comment?query * Doc Brown's Chemistry Clinic updated 10-06-09 *

   air      aluminium      bauxite      burn      carbon      chemical      coke      concentrated      cryolite      decomposed      dioxide      electric      electrolysis      exothermic      free      gold      haematite      high      impure      ions      iron      least      less      limestone      melted      monoxide      more      negative      negatively      ores      oxidation      oxide      oxides      oxidised      oxygen      position      positive      positively      pure      reactive      reactivity      redox      reduces      reduction      removed      replaced      slag      sulphate      top   
Q1 The Earth's crust contains metals and metal compounds. These are always found mixed with other substances. In , the metal or metal compound is enough to make it economic to extract the metal. An unreactive metal like , is found in the Earth as the metal itself and so separation is not always needed. The reactivity series of metals lists metals in order of their reactivity, the most reactive metal being placed at the of the list and the reactive at the bottom.

Q2 A more metal can displace a reactive metal from its compounds. The non-metal elements and hydrogen will also displace less reactive metals from their . You can use the of a metal in the series to predict how the metal can be extracted from a compound.

Q3 Often an ore contains a metal or a substance which can easily be changed into a metal oxide. To extract the metal, the oxygen must be from the metal oxide. This is called . How a metal is extracted from its ore depends on how the metal is. A metal such as iron, which is reactive than carbon, can therefore be extracted from its ore using carbon. Metals which are reactive than carbon, like are extracted by

Q4 The solid raw materials used in the blast furnace are an iron ore called , the fuel and reducing agent and limestone. The 4th raw material is hot (oxygen supply) is blown into the furnace and this causes the coke to burn forming and releasing energy (an reacion). At the high temperatures in the furnace the carbon dioxide reacts with coke to form . The carbon monoxide the iron oxide in the iron ore (by removing the oxygen) to form molten iron which flows to the bottom of the furnace. The carbon monoxide combines with the from the iron ore to produce carbon dioxide. This is called oxidation. The is added to remove acidic impurities like silica (silicon dioxide), forming a molten that floats on the surface of the molten .

Q5 Reactive metals such as aluminium are extracted by electrolysis. When substances which are made of are dissolved in water, or , they can be broken down () into simpler substances by passing an current through them. This process is called electrolysis. When an ionic substance is melted or dissolved in water the ions are to move about. During electrolysis, charged ions for example, metal ions move to the negative electrode, and charged ions move to the positive electrode. During electrolysis, gases may be given off, or metals deposited at the electrodes.

Q6 The raw material for producing aluminium is , purified from an aluminium ore called . Because aluminium oxide has a very melting point it is dissolved in a molten aluminium compound called to lower the melting point. Both electrodes are made of . The aluminium forms at the electrode and oxygen forms at the electrode. This makes the positive electrodes away quickly so that they frequently have to be as they are to carbon dioxide.

Q7 Copper can be purified by electrolysis using a positive electrode made of the copper and a negative electrode made of of copper. Both are dipped into a solution of copper containing copper (Cu2+).

Q8 At the negative electrode, positively charged ions gain electrons, a process called . At the positive electrode negatively charged ions lose electrons in a process called . In a chemical reaction oxidation always occurs with . These are called reactions.