Activity 1. Using a calorimeter: Measuring the energy change during chemical reactions 

Calorimetry is used to measure the energy change of a chemical reaction or the energy content of food. The temperature change that occurs in the calorimeter as a result of the chemical reaction is measured. The energy required to heat the water in a calorimeter can then be calculated using q = mcΔT. 

 60 minutes

 QLDCH11_MA1.spklab

Activity 2. Derive the empirical formula of a compound from reactions involving mass changes 

Elements always combine in a definite mass ratio to form compounds. In this experiment, magnesium metal is heated in oxygen to form the compound magnesium oxide. By finding the mass of the original magnesium and that of the magnesium oxide, the percentage of magnesium in magnesium oxide can be calculated. The mole ratio of magnesium to oxygen can also be determined so that the empirical formula can be derived. 

 30 minutes

 QLDCH11_MA2.spklab

Molecular modelling is a useful way to represent covalent molecules in three dimensions and to relate this to two-dimensional representations such as valence structures.

Activity 4. The molar volume of hydrogen

In this experiment, you will determine the number of moles of hydrogen gas produced in a reaction. From measurements of the gas volume and pressure, the molar volume of hydrogen at standard temperature and pressure (STP) can be calculated. 

 QLDCH11_MA4.spklab

Activity 5. Precipitation reactions

When two clear solutions containing dissolved ionic salts are mixed together, an insoluble product called a precipitate may form and settle out of the mixture. Knowing which ions form precipitates is essential in many industrial processes and in monitoring and maintaining the water quality in natural waterways.

Ethanoic acid, CH3COOH(aq) ionises to only a small extent in water. Hydrochloric acid, HCl(aq) ionises completely in water. This means that the same concentration of the two acids produce different numbers of hydrogen ions and have different pH values.