Atoms, molecules and stoichiometry

Formulae, Equations and the MoleSign up

know the terms 'atom', 'element', 'ion', 'molecule', 'compound', 'empirical formula' and 'molecular formula' · know that the mole (mol) is the unit for the amount of a substance and be able to perform calculations using the Avogadro constant L (6.02 x 10^23 mol^-1) · write balanced full and ionic equations, including state symbols, for chemical reactions · understand the terms: (i) 'relative atomic mass' based on the 12C scale; (ii) 'relative molecular mass' and 'relative formula mass', including calculating these values from relative atomic masses (the term 'relative formula mass' should be used for compounds with giant structures); (iii) 'molar mass' as the mass per mole of a substance in g mol^-1; (iv) parts per million (ppm), including gases in the atmosphere · calculate the concentration of a solution in mol dm^-3 and g dm^-3 (titration calculations are not required at this stage)

Stoichiometric Calculations: Masses, Gas Volumes and Limiting ReagentsSign up

be able to use experimental data to calculate empirical and molecular formulae · be able to use chemical equations to calculate reacting masses and vice versa, using the concepts of amount of substance and molar mass · be able to use chemical equations to calculate volumes of gases and vice versa, using: (i) the concepts of amount of substance; (ii) the molar volume of gases; (iii) the expression pV = nRT for gases and volatile liquids · be able to calculate percentage yields and percentage atom economies (by mass) in laboratory and industrial processes, using chemical equations and experimental results (atom economy = molar mass of the desired product / sum of the molar masses of all products x 100%) · be able to determine a formula or confirm an equation by experiment, including evaluation of the data · CORE PRACTICAL 1: Measurement of the molar volume of a gas

Ionic Equations and Reaction ObservationsSign up

be able to relate ionic and full equations, with state symbols, to observations from simple test-tube experiments, to include: (i) displacement reactions; (ii) typical reactions of acids; (iii) precipitation reactions

Mass Spectrometry and Relative MassesSign up

understand the basic principles of a mass spectrometer and be able to analyse and interpret mass spectra to: (i) deduce the isotopic composition of a sample of an element; (ii) calculate the relative atomic mass of an element from relative abundances of isotopes and vice versa; (iii) determine the relative molecular mass of a molecule, and hence identify molecules in a sample; (iv) understand that ions in a mass spectrometer may have a 2+ charge · be able to predict mass spectra, including relative peak heights, for diatomic molecules, including chlorine, given the isotopic abundances

Volumetric Analysis and Titration CalculationsSign up

be able to calculate solution concentrations, in mol dm^-3 and g dm^-3, including simple acid-base titrations using the indicators methyl orange and phenolphthalein · CORE PRACTICAL 3: Finding the concentration of a solution of hydrochloric acid · understand how to minimise the sources of measurement uncertainty in volumetric analysis and estimate the overall uncertainty in the calculated result · CORE PRACTICAL 4: Preparation of a standard solution from a solid acid and use it to find the concentration of a solution of sodium hydroxide