Back to quiz

6. What is the definition of the standard enthalpy of combustion?

  • the change in enthalpy that occurs when an acid and base undergo a neutralization reaction to form water and a salt
  • The enthalpy change when 10g of a substance completely reacts with oxygen under standard conditions.
  • The enthalpy change when one mole of a substance completely reacts with oxygen under standard conditions
  • enthalpy change when 1 mol of atoms in the gas phase is formed from its element in its defined physical state under standard condition

7. Which of these is an enthalpy change of formation?

  • CH4(g) + 2 O2(g) ---> CO2(g) + 2 H2O(g)
  • Al(s) + 3/2 Cl2(g) ---> AlCl3(s)
  • Mg(s) ---> Mg(g)
  • HCl(aq) + NaOH(aq) ---> NaCl(aq) + H2O(l)

8. Hess's law states that the total enthalpy change is dependant on the route taken

  • False
  • True

9. Which of these is mean bond enthalpy?

  • CH4(g) --> C(g) + 4H(g) ΔH = 4q
  • CH4(g) --> CH3(g) + H(g) ΔH = q

10. Photosynthesis is an example of an endothermic reaction

  • True
  • False