M2 - Foundations in chemistry

• What is the definition of strong acids?

  Strong acids fully dissociate in solution
• What happens when hydrogen chloride (HCl) is dissolved in water?

  100% of the product will be ions
• What is the dissociation equation for HCl in water?

  HCl (aq) → H (aq) + Cl (aq)
• What ions are released when strong acids dissociate?

  Hydrogen ions, H (aq)
• What is the definition of strong bases?

  Strong bases fully dissociate in solution
• What happens when sodium hydroxide (NaOH) is dissolved in water?

  100% of the product will be ions
• What is the dissociation equation for NaOH in water?

  NaOH (aq) → Na (aq) + OH (aq)
• How do weak acids dissociate in solution?

  Weak acids only partially dissociate in solution
• What is established in an equilibrium reaction involving weak acids?

  Both reactants and products are present
• What is the dissociation equation for ethanoic acid (CH3COOH)?

  CH3COOH (aq) ⇌ CH3COO (aq) + H (aq)
• How do weak bases dissociate in solution?

  Weak bases only partially dissociate in solution
• What is established in an equilibrium reaction involving weak bases?

  An equilibrium is established with reactants and products
• What is the dissociation equation for ethylamine (C2H5NH2)?

  C2H5NH2 (aq) + H2O (l) ⇌ C2H5NH3 (aq) + OH (aq)
• What is a neutralisation reaction?

  • An acid (pH < 7) reacts with a base (pH > 7)
  • Produces water (pH = 7) and a salt
  • Proton of the acid reacts with hydroxide of the base
• What is produced in a neutralisation reaction?

  Water and a salt
• What are spectator ions in a neutralisation reaction?

  They are not involved in water formation
• How can the name of the salt produced in a neutralisation reaction be predicted?

  From the acid that has reacted
• What is the typical reaction of a metal and an acid?

  Acid + metal → salt + hydrogen
• What determines the extent of reaction between a metal and an acid?

  The reactivity of the metal and strength of the acid
• What is the reaction equation for hydrochloric acid and zinc?

  2HCl (aq) + Zn (s) → ZnCl2 (aq) + H2 (g)
• What happens with very reactive metals and acids?

  They react dangerously and are not usually used
• What happens with metals low in reactivity and dilute acids?

  They do not react at all
• How do stronger acids react with metals compared to weak acids?

  Stronger acids react more vigorously
• What signs of reaction differ between strong and weak acids with metals?

  Faster reaction, more effervescence, more exothermic
• What products are formed when an acid reacts with a metal oxide?

  Salt and water
• What is the reaction equation for hydrochloric acid and calcium oxide?

  2HCl (aq) + CaO (s) → CaCl2 (aq) + H2O (l)
• What products are formed when an acid reacts with a metal hydroxide?

  Salt and water
• What is the reaction equation for sulfuric acid and magnesium hydroxide?

  H2SO4 (aq) + Mg(OH)2 (s) → MgSO4 (aq) + 2H2O (l)
• What products are formed when an acid reacts with a metal carbonate?

  Salt, water, and carbon dioxide
• What is the reaction equation for hydrochloric acid and calcium carbonate?

  2HCl (aq) + CaCO3 (s) → CaCl2 (aq) + H2O (l) + CO2 (g)
• What is volumetric analysis in chemistry?

  • Uses volume and concentration of one reactant
  • Determines concentration of another unknown solution
  • Commonly performed using titration
• What equipment is used in volumetric analysis?

  Volumetric pipette and burette
• What must be prepared before performing a titration?

  The standard solution must be prepared
• What are key pieces of apparatus used in titration?

  Beaker, burette, volumetric pipette
• What are the steps to make a standard solution?

  1. Use three decimal place balances
  2. Use volumetric flasks for accuracy
  3. Prepare solutions with known concentrations

  
• How is concentration expressed?

  Moles per unit volume, mass per unit volume
• What is the precision of a burette?

  Marked to a precision of 0.10 cm
• How is uncertainty recorded for a burette reading?

  To ±0.05 cm
• What indicates the end point in a titration?

  Use of an indicator shows the end point
• What are the steps in a titration?

  1. Measure known volume with volumetric pipette
  2. Place solution in conical flask
  3. Fill burette to 0.00 cm
  4. Add indicator to conical flask
  5. Open burette tap to add solution
  6. Slow flow near end point, add dropwise
  7. Close tap after colour change
  8. Repeat for concordant results