topic 4- chemical change

• What is oxidation in terms of oxygen gain?

  When a substance gains oxygen
• What is reduction in terms of oxygen loss?

  When a substance loses oxygen
• What does the reactivity series of metals indicate?

  Order of metals based on reactivity
• What happens to metals above hydrogen in the reactivity series when reacting with acids?

  They react to produce hydrogen gas
• How does the reactivity of metals with acids change?

  More reactive metals react quicker and violently
• What is the behavior of metals below hydrogen in the reactivity series with acids?

  They do not react with acids
• Which metals typically react with water?

  Mostly Group I and II metals
• How are unreactive metals found in nature?

  In their natural state
• How can metals less reactive than carbon be extracted?

  Reduction with carbon
• What happens during the reduction of metals with carbon?

  Carbon displaces the metal in metal oxide
• How are metals more reactive than carbon extracted?

  By electrolysis
• How are oxidation and reduction defined in terms of electron transfer?

  Oxidation is loss of electrons
• What is the general equation for a reaction between metals and acids?

  Metal + acid → salt + hydrogen
• What type of reaction occurs between metals and acids?

  Redox reaction and displacement reaction
• Which metals in the reactivity series will react with acid?

  Those above hydrogen
• What is the general equation for a neutralisation reaction?

  Base + acid → salt + water
• What is the general equation for the reaction between metal carbonate and acid?

  Metal carbonate + acid → salt + water + carbon dioxide
• What is the general equation for the reaction between metal oxides and acids?

  Metal oxide + acid → salt + water
• What is a redox reaction?

  A reaction where both oxidation and reduction occurs
• How is a soluble salt formed?

  • React excess acid with insoluble chemical
  • Filter off leftovers
  • Crystallise the product
• What do acids produce in aqueous solutions?

  Hydrogen ions
• What do alkalis produce in aqueous solutions?

  Hydroxide ions
• What are bases, acids, and alkalis?

  • Bases neutralise acids
  • Acids produce hydrogen ions
  • Alkalis are soluble bases producing hydroxide ions
• What is the pH scale?

  Measure of acidity/alkalinity of a solution
• What does a pH of 7 indicate?

  Neutral solution
• What is the short ionic form of the general equation for a neutralisation reaction?

  H+ + OH− → H2O
• What is a strong acid?

  Completely ionised in aqueous solution
• What is a weak acid?

  Partially ionised in aqueous solution
• What happens to pH as the concentration of H+ increases?

  pH decreases
• What is the general equation for a neutralisation reaction?

  H+ + OH− → H2O
• What is a concentrated acid?

  More moles of acid per unit volume
• What is a dilute acid?

  Solutions of low concentrations
• What change occurs in hydrogen ion concentration as pH decreases by one unit?

  Increases by a factor of 10
• What is electrolysis?

  Passing electric current through ionic substances
• What is an electrolyte?

  Liquid/solution that conducts electricity
• What is a cathode?

  Negative electrode
• What is an anode?

  Positive electrode
• What occurs at the cathode during electrolysis?

  Reduction occurs
• What occurs at the anode during electrolysis?

  Oxidation occurs
• What is discharged at the cathode in aqueous electrolysis?

  The less reactive element discharges