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Essential ideas:
  • All measurement has a limit of precision and accuracy, and this must be taken into account when evaluating experimental results.
  • Graphs are a visual representation of trends in data.
  • Analytical  techniques  can be used  to determine  the structure  of a compound,  analyse  the composition  of a substance  or determine  the purity  of a compound. Spectroscopic techniques are used in the structural identification of organic and inorganic compounds.
11.1 Quantitative and qualitative data
Understandings:
Qualitative data includes all non-numerical information obtained from observations not from measurement.
Quantitative data are obtained from measurements,  and are always associated with random errors/uncertainties, determined by the apparatus, and by human limitations such as reaction times.
11.1 Absolute and percentage uncertainties 
Applications and skills:
Record uncertainties in all measurements  as a range (+) to an appropriate precision.
Calculating uncertainties worksheet
Calculating uncertainties worksheet answer key
11.1 Random and systematic errors
Understandings:
Experimental design and procedure usually lead to systematic errors in measurement, which cause a deviation in a particular direction.
Repeat trials and measurements  will reduce random errors but not systematic errors.
Applications and skills:
Distinction between random errors and systematic errors.
Discussion of systematic errors in all experimental work, their impact on the results and how they can be reduced.
11.1 Propagation of uncertainties
Understandings:
Propagation of random errors in data processing shows the impact of the uncertainties on the final result.
Applications and skills:
Propagation of uncertainties in processed data, including the use of percentage uncertainties.
11.1 Percentage error 
Applications and skills:
Calculation of percentage error when the experimental result can be compared with a theoretical or accepted result.
11.3 Index of hydrogen deficiency 
Understandings:
The degree of unsaturation or index of hydrogen deficiency (IHD) can be used to determine from a molecular formula the number of rings or multiple bonds in a molecule.
11.3 Infrared spectroscopy 
Understandings:
Mass spectrometry (MS), proton nuclear magnetic resonance spectroscopy (1H NMR) and infrared spectroscopy (IR) are techniques that can be used to help identify compounds and to determine their structure.
Applications and skills:
Deduction of information about the structural features of a compound from percentage composition data, MS, 1H NMR or IR.
Guidance:
The regions employed for each technique should be understood.
 The operating principles are not required for any of these methods.
11.3 Mass spectrometry 
Understandings:
Mass spectrometry (MS), proton nuclear magnetic resonance spectroscopy (1H NMR) and infrared spectroscopy (IR) are techniques that can be used to help identify compounds and to determine their structure.
Applications and skills:
Deduction of information about the structural features of a compound from percentage composition data, MS, 1H NMR or IR.
11.3 Proton nuclear magnetic resonance spectroscopy (1H NMR) 
Understandings:
Mass spectrometry (MS), proton nuclear magnetic resonance spectroscopy (1H NMR) and infrared spectroscopy (IR) are techniques that can be used to help identify compounds and to determine their structure.
Applications and skills:
Deduction of information about the structural features of a compound from percentage composition data, MS, 1H NMR or IR.
11.3 1H NMR - how to determine number of peaks in NMR spectrum
In this video, I take a look at how to determine the number of peaks on a 1H NMR spectrum of an organic compound by looking at its structure formula. Note that I do not cover splitting of the peaks in this video as this covered in the HL part of the syllabus.