| Question 1: The combustion of propane, CH3CH2CH3, produces carbon dioxide, water vapour and heat. Write the balanced chemical equation for this reaction and include the heat on the correct side of the reaction. |
Answer to Question 1:
Combustion reaction always involves oxygen, O2 (g).
Combustion reaction involving hydrocarbons (compounds made up of carbon and hydrogen) produce carbon dioxide, CO2 (g), and H2O (g).
Combustion reaction involving hydrocarbons produces heat. (i.e. Heat is on the product side.)
The unbalanced reaction is:
CH3CH2CH3 (g) + O2 (g) 
CO2 (g) + H2O (g) + heat
The balanced reaction is:
CH3CH2CH3 (g) + 5 O2 (g) 3 CO2 (g) + 4 H2O (g) + heat
| Question 2: Write the word equation for the following two reactions and determine if the reactions are endothermic or exothermic: (a) H2 (g) + Cl2 (g) 2 HCl (g) + 185 kJ |
Answer to Question 2a:
Word equation:
Hydrogen gas reacts with chlorine gas produces hydrogen chloride gas and heat.
Since heat is on the product side of the reaction, this is an exothermic reaction.
| Question 2: Write the word equation for the following two reactions and determine if the reactions are endothermic or exothermic: (b) 285 kJ + 3 O2(g) 2 O3(g) |
Answer to Question 2b:
Word equation:
heat + oxygen gas produces ozone gas.
Since heat is on the reactant side of the reaction, this is an endothermic reaction.
