Chemical changes

• The gain of oxygen or the loss of electrons


  What is oxidation?
• The loss of oxygen or the gain of electrons


  What is reduction?
• Potassium, sodium, calcium, magnesium, aluminium, carbon, zinc, iron, tin, lead, hydrogen, copper, silver, gold, platinum


  What is the order of the reactivity series?
• How easily a metal loses electrons

  What is meant by "reactivity"?
• A metal salt and hydrogen


  What is produced when a metal reacts with an acid?
• A metal hydroxide solution and hydrogen


  What is produced when the alkali metals react with water?
• For comparison


  Why does the reactivity series of metals often contain carbon and hydrogen?
• A more reactive metal will displace the less reactive metal from its salt


  What happens in a displacement reaction?
• By reduction with carbon (heat then with carbon)


  How can metals that are less reactive that carbon be extracted from their oxides?
• Hydroxide (OH-)


  What ions is found in all alkalis?
• Hydrogen, H+


  What ion is found in all acids?
• The acidity or alkalinity is a substance


  What is the pH scale a measure of?
• 7


  What is a neutral pH?
• Between 0 and 6 (Closer to 0, the stronger the acid)


  What is the range of acidic pH?
• Between 8 and 14 (Closer to 14, the stronger the alkali)


  What is the range of alkaline pH?
• Using a pH probe or universal indicator


  How can we measure the pH?
• Dyes that change colour depending on if they're in an acidic or alkaline solution


  What is an indicator?
• Red


  What colour does litmus paper go in an acid?
• Blue


  What colour does litmus paper go in an alkali?
• Acid + metal hydroxide = salt + water


  What is the neutralisation equation for a acid and metal hydroxide?
• H+ + OH- = H2O


  What is the neutralisation equation for an acid and alkali reacting?
• Acid + metal oxide = salt + water


  What is the neutralisation equation for an acid and a metal oxide?
• Acid + metal carbonate = salt + water + carbon dioxide


  What is the neutralisation equation for an acid and a metal carbonate?
• Metal name, name from acid


  How do we name the salts in a neutralisation equation?
• Chloride salts


  What type of salt does hydrochloric acid produce?
• Nitrate salts


  What type of salts does nitric acid produce?
• Sulphate salts


  What type of salts does sulphuric acid produce?
• The H+ ions are fully ionised in water


  What is meant by a strong acid?
• The H+ ions are not fully ionised in water


  What is meant by a weak acid?
• The concentration of the H+ ions in a solution


  What ions does pH measure?
• The concentration of hydrogen ions has increased or decreased by 10


  What does a change of one unit in pH indicate?
• The use of an electrical current to break down compounds containing ions into their elements


  What is electrolysis?
• What is the positive electrode during electrolysis?

  The anode
• What is the negative electrode during electrolysis?

  The cathode
• What are the negative ions called in electrolysis?

  Anions
• What are the positive ions called in electrolysis?

  Cations
• What happens at the cathode during the electrolysis of ionic substances?

  The metal goes to the cathode because metals always loose electrons in ionic bonding and is reduced (gains electrons)
• What happens at the anode during the electrolysis of ionic substances?

  The non-metal element forms at the anode and is oxidised (looses electrons)
• What would happen during the electrolysis of lead bromide?

  The lead would form at the cathode and gain 2 electrons to form pure lead, the bromide would form at the anode as a gas and gain electrons
• What happens in a redox reaction?

  Both oxidation and reduction take place