Chemistry C5

• What is formed when acids react with metals?

  Salts
• What is a salt?

  A compound with hydrogen replaced by metal
• What salt is formed when nitric acid reacts with sodium?

  Sodium nitrate, NaNO3
• What are the types of salts formed from different acids?

  • Hydrochloric acid ➞ metal chloride
  • Sulfuric acid ➞ metal sulfate
  • Nitric acid ➞ metal nitrate
• What is the formula for hydrochloric acid?

  HCl
• What ions are formed in solution from hydrochloric acid?

  H+ and Cl−
• What is the reactivity of potassium?

  High reactivity
• What happens when sodium reacts with water?

  It fizzes and gives off hydrogen gas
• What is the reactivity of gold?

  Low reactivity
• What is the reactivity series?

  Order of metals by reactivity
• How is oxidation defined in terms of electrons?

  Loss of electrons
• How is reduction defined in terms of electrons?

  Gain of electrons
• In a displacement reaction, what happens to iron atoms?

  They are oxidised
• In a displacement reaction, what happens to copper ions?

  They are reduced
• What is a spectator ion?

  An ion that does not change in reaction
• What is the ionic equation for the displacement reaction of copper sulfate and iron?

  Fe(s) + Cu2+(aq) ➞ Fe2+(aq) + Cu(s)
• What happens to iron in the displacement reaction?

  It loses two electrons
• What happens to copper ions in the displacement reaction?

  They gain two electrons
• What are the steps for writing an ionic equation?

  1. Check symbol equation is balanced
  2. Identify all aqueous ionic compounds
  3. Write those compounds out as ions
  4. Remove spectator ions
• What is a displacement reaction?

  A more reactive element replaces a less reactive one
• What is the reaction of copper sulfate with iron?

  CuSO4(aq) + Fe(s) ➞ FeSO4(aq) + Cu(s)
• What do acids release when dissolved in water?

  H+ ions
• What are the three main acids?

  Sulfuric, nitric, hydrochloric
• What do alkalis release when dissolved in water?

  OH− ions
• What does the pH scale measure?

  Acidity and alkalinity
• What pH indicates an acidic solution?

  pH < 7
• What pH indicates an alkaline solution?

  pH > 7
• What pH indicates a neutral solution?

  pH = 7
• What can indicators show?

  If a substance is an acid or alkali
• What does a universal indicator do?

  Shows approximate pH of a solution
• What is the ionic equation for the reaction of hydrochloric acid with sodium hydroxide?

  H+(aq) + OH−(aq) ➞ H2O(l)
• What do acids react with to form salts and hydrogen gas?

  Some metals
• What do acids react with to form salts and water?

  Metal hydroxides
• What do acids react with to form salts and water in addition to carbon dioxide?

  Metal carbonates
• What do bases do in neutralisation reactions?

  Neutralise acids to form water
• What is the method to produce a solid salt from an insoluble base?

  Crystallisation
• What are the steps for crystallisation?

  1. Choose acid and base
  2. Heat dilute acid
  3. Add base and stir
  4. Add base until excess
  5. Filter unreacted base
  6. Evaporate water
  7. Collect salt crystals
• What must be ensured when writing symbol equations?

  Number of each atom must be equal
• What is the balanced equation for the reaction of hydrogen and oxygen?

  2H2 + O2 ➞ 2H2O
• What are the state symbols for solid, liquid, gas, and aqueous?

  (s), (l), (g), (aq)