Chemical Changes

• How are metal oxides produced?


  Metals react with oxygen
• What reaction is metal oxides being produced, why?

  Oxidation,metal gains oxygen
• What is reduction?


  Loss of oxygen, gain of electrons
• What is oxidation?


  Gain of oxygen, Loss of electrons
• What is a strong acid completely ionizing in?

  Aqueous solutions
• Examples of strong acids?


  -Hydrochloric acid

  -Sulfuric acid

  -Nitric acid
• What is a weak acid partially ionizing in?


  -Aqueous solutions
• Examples of Weak acids?


  -Carbonic acid

  -Citric acid

  -Ethanoic acid
• For a given concentration of aqueous solutions, what happens to the Ph if the acid is stronger?

  Ph gets lower
• What is the reactivity series?

  Metals arranged in order of their reactivity
• What is the speed of a reaction indicated by when salt + hydrogen is produced?

  Rate at which bubbles of hydrogen are given off
• What makes a reaction faster in metals?

  More reactive the metal is
• What is the ph of aqueous solutions of alkalis?

  Greater than 7
• What do acids produce in aqueous solutions?


  Hydrogen ions (H+)
• What do aqueous solutions of alkalis contain?

  Hydroxide ions (OH-)
• What happens in neutralisation reactions between an acid and an alkali?


  Hydrogen ions (H+) react with Hydroxide ions (OH-) to produce water
• What is the PH scale?


  Scale used to measure the acidity or alkalinity of a solution
• When does the PH scale start/end at?

  0-14
• What PH is neutral?

  7
• What PH do acids have?

  0-6
• What PH do alkalis have?

  8-14
• What PH do aqueous solutions of acids have?

  Less than 7
• What are acids neutralised by?

  Alkali

  Base

  Metal Carbonate
• When an acid is neutralised by an alkali/base what does it produce?


  Salt & Water
• When an acid is neutralised by metal carbonates what does it produce?


  Metal & Salt & Carbon dioxide
• What does the particular salt produced in a reaction depend on?

  -+ ions in the base/alkali/metal carbonate

  -The acid used
• Where are unreactive metals found?


  -In the Earth as metals
• How are most metals found?

  As compounds, that require chemical reactions to extract the metal
• How can metals less reactive than carbon be extracted from their oxides?

  Reduction with Carbon
• In terms of electrons, what is oxidation?

  Loss of electrons
• In terms of electrons, What is reduction?

  Gain of electrons
• What is electrolysis?


  Passing an electric current through electrolytes causes the ions to move to the electrodes. Positively charged ions move to the negative electrode (the cathode), and negatively charged ions move to the positive electrode (the anode). Ions are discharged at the electrodes producing elements.
• How can elements be extracted from molten compounds?

  By electrolysis
• Why is electrolysis used?


  -If metal is too reactive to be extracted by reduction with carbon

  -If the metal reacts with carbon
• Why are large amounts of energy used in electrolysis ?


  -To melt the compounds

  -Produce an electrical current
• Why must the positive electrode be continually replaced?

  They gradually burn away
• What happens to the ions in an ionic compound is metal/dissolved in water?

  Ions are free to move within the solution
• What are electrolytes?


  Liquids/Solutions that are able to conduct electricity
• What happens when an electric current are passed through electrolytes?

  Ions move to the electrodes
• What ions move towards the cathode?


  + charged ions