# Instructional Objectives

(a) define and use the terms relative atomic, isotopic, molecular and formula masses, based on the ^{12}C scale

(b) define and use the term molein terms of the Avogadro constant

(c) analyse mass spectra in terms of isotopic abundances and molecular fragments[knowledge of the working of the mass spectrometer is not required]

(d) calculate the relative atomic mass of an element given the relative abundances of its isotopes, or its mass spectrum

(e) define and use the terms empirical and molecular formulae

(f) calculate empirical and molecular formulae, using combustion data or composition by mass

(g) write and/or construct balanced equations

(h) perform calculations, including use of the mole concept, involving:

(i) reacting masses (from formulae and equations)

(ii) volumes of gases (e.g. in the burning of hydrocarbons)

(iii) volumes and concentrations of solutions

When performing calculations, candidatesâ€™ answers should reflect the number of significant figures given or asked for in the question.

When rounding up or down, candidates should ensure that significant figures are neither lost unnecessarily nor used beyond what is justified

(i) deduce stoichiometric relationships from calculations such as those in (h)

# Teaching Process

- All the above concepts are taught with hand on experiments (Calculation with liquids) and numerical calulations

# Suggested Reading

- http://www.sizes.com/units/atomic_mass_unit.htm
- http://en.wikipedia.org/wiki/Atomic_mass_unit#History
- CD-Rom given with textbook
- THE MOST IMPORTANT LINK - http://www.chemguide.co.uk/CIE/sect1menu.html#top
- Raymond Chang (9th edition) - 1 st chapter - Handling numbers (Page 21 till the end of the chapter) and Chapter 3 - Full

# Activities

- Titration is taught in detail. Students will perform titration with reactions prescribed in the syllabus

# Assignments and Evaluation

- Seminar by students on C-12 isotope as standard
- Check up and End of chapter questions from the text book
- Internal assessment test at the end of the chapter
- Assignment and solution sheet is attached