​Qualitative analysis

• Based on chemical or physical properties

• ​reactivity

• solubility

• melting point

• mass spectra

• etc. 

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Quantitative analysis​

• Amount or concentration expressed as numerical values and appropriate units. 

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Precision

• the closeness of agreement between independent test results 

• lower random error= higher precision

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Accuracy

• the closeness of the agreement between results and the true

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Significant Figures

• Number of figures reflecting the precision of a given measurement

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Systematic errors

• Flaw in the design of the experiment or misuse of equipment

  • Instrumental errors

    • Example:​ Faulty calibration of equipment

  • Experimental methodology errors

    • Example:​ Calorimeter insulation

  • Personal errors

    • Example:​ Reading of graduated cylinder

• Affect accuracy

• improve: adopt greater care to experimental design

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Random erros

• Cannot be eliminated, but reduced--> repeated measurement 

• affect precision

• Example: estimating quamtity between graduations

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Absolute and relative uncertainty

• Absolute: related to measurement

• Relative: related to size of measurement (%)

​Slope of a line

• tangent at a certain point

Intercept

• extrapolation

• y=ax+b

Best fit line

• Trendline

• Need R squared

Sketch

• Labelled but unscaled axis

• show proportionality

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Graph

• Labelled and scaled axis 

• quantitative measurement

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​Index of hydrogen deficiency (IHD)

• used to determine number of rings or multiple bonds in a molecule

• degree of unsaturation is used to calculate the number of pi bonds and number of rings where:

  • Double bond​: one degree

  • Triple bond: two degree

  • Ring:one degree

  • Aromatic ring: four degree

• OR: IHD = 0.5(2c+2-h-x+n)​

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Infrared spectroscopy​

• Identifies various functional groups

• based on spring model

  • symmetric stretch ​

  • symmetric bend

  • asymmetric stretch

• Fingerprint region should not be taken into consideration​

Proton nuclear magnetic resonance (1HNMR)

• Information between different chemical environments of hydrogen atoms

• Table 27 of data booklet

• shows the relative number of hydrogen atoms present

​Mass spectrometry (MS)

• Highly energetic ions, may break in smaller fragments, some of which may be ions.

• Section 28 of data booklet shows fragmentation pattern