Worksheet Chapter 3: The Mole Concept, Chemical Formulae and Equations

1. True or False: One mole of oxygen gas (O2) and one mole of carbon dioxide gas (CO2) occupy the same volume under the same temperature and pressure.

2. True or False: The molecular formula and empirical formula of water (H2O) are identical.

3. Which experimental set-up is used to determine the empirical formula of reactive metals such as zinc or magnesium?

4. Explain step-by-step why the combustion method using a crucible is suitable for determining the empirical formula of magnesium oxide, but UNSUITABLE for determining the empirical formula of lead(II) oxide.

5. A sample of oxide of iron contains 1.12 g of iron and 0.48 g of oxygen. Determine the empirical formula of this iron oxide. [RAM: Fe=56, O=16]

6. Calculate the relative formula mass (Fr) of ammonium sulfate, (NH4)2SO4. [Relative atomic mass: N=14, H=1, S=32, O=16]

7. Copper(II) carbonate decomposes upon heating according to the equation: CuCO3 (s) -> CuO (s) + CO2 (g) If 12.4 g of CuCO3 is heated completely, calculate the volume of CO2 gas liberated at room conditions. [RAM: Cu=64, C=12, O=16; Molar volume at room conditions = 24 dm3 mol-1]

8. Define the term 'molar volume of gas' and state its value at room conditions.

9. 8.0 g of copper(II) oxide powder reacts completely with dilute sulfuric acid according to the following balanced equation: CuO (s) + H2SO4 (aq) -> CuSO4 (aq) + H2O (l) (a) Calculate the number of moles of CuO reacted. (b) Determine the mass of copper(II) sulfate formed. (c) If the experiment yields 14.4 g of copper(II) sulfate crystals, calculate the percentage yield. [RAM: Cu=64, O=16, H=1, S=32]

10. Fill in the blank: The number of particles contained in 1 mole of any substance is known as the ________ constant.