IB chemistry

• Lavoisier's experiments contradicted the belief that mass would be lost during combustion as phlogiston was released
• Lavoisier's work contained some of the first examples of quantitative chemistry and the law of conservation of mass
• The discovery of oxygen by Joseph Priestly and Carl Scheele invalidated the phlogiston theory
• Paradigm shift


  The dominant paradigm or belief is replaced by a new paradigm
• William Lawrence Bragg (1890–1971) shared the 1915 Nobel Prize in Physics with his father, Sir William Henry Bragg, for their analysis of crystal structures using X-rays, which led to the development of X-ray crystallography
• William Lawrence Bragg: 'A wrong theory is always so much better than no theory at all.'
• Chemistry is sometimes described as the "central science" and at the centre of chemistry lies atomic theory
• In 1981, Gerd Binnig and Heinrich Rohrer invented the scanning tunnelling microscope (STM), an electron microscope that generates three-dimensional images of surfaces at the atomic level
• The Nobel Prize in Physics in 1986 was awarded to Binnig and Rohrer for their ground-breaking work
• The Nobel Prize in Chemistry is awarded annually by the Royal Swedish Academy of Sciences, Stockholm, Sweden
• The Nobel Prize website gives information about the various Nobel Prize winners in chemistry and other fields of science and medicine
• Chemistry was deemed the most important science for the work of Alfred Nobel
• Shroud of Turin


  A linen cloth believed by many people to be the one used to wrap the body of Jesus Christ after his death
• In 1988 the Vatican in Rome commissioned three independent analytical laboratories based at the University of Oxford, UK, the Swiss Federal Institute of Technology, and the University of Arizona, USA, to carry out carbon-14 dating on the Shroud
• All three results confirmed that the samples taken from the cloth originated between 1260 and 1390 AD, suggesting that the Shroud was not the burial cloth of Jesus
• In July 2013 Giulio Fanti and co-workers from the University of Padua, Italy, published research in the journal Vibrational Spectroscopy which shows a two-way relationship between age and a spectral property of ancient flax textiles
• The media reported their findings worldwide, claiming that the results dated the Shroud of Turin between 300 BC and 400 AD, which could date from the time of Christ
• An app (application) has been developed by the Diocese of Turin in Italy and the International Centre of Sindonology (scientific study of the Shroud)
• The app is named Shroud 2.0 and using this you can explore the various images, scientific and theological interpretations
• Developments in scientific research follow improvements in apparatus – the use of electricity and magnetism in Thomson's cathode rays
• Theories being superseded – quantum mechanics is among the most current models of the atom
• Use theories to explain natural phenomena – line spectra explained by the Bohr model of the atom
• Samuel Beckett (1906–1989), Irish novelist, poet, and playwright who won the Nobel Prize in Literature in 1969: 'What visions in the dark of light!'
• The wavelengths of the different types of waves in the EMS are given in section 3 of the Data booklet
• In the 1600s Sir Isaac Newton showed that if sunlight is passed through a glass prism the visible light is separated into different colours generating a continuous spectrum
• IB, May 2010
• Order of increasing energy of the orbitals within a single energy level


  s < p < d < f
• IB, May 2009
• Condensed electron configuration for Co3+

  [Ar]3d6
• Draw and label an energy level diagram for the hydrogen atom


  Show how the series of lines in the ultraviolet and visible regions of its emission spectrum are produced, clearly labelling each series
• IB, Specimen Paper
• Atoms are often drawn as spheres
• Comment on the use of this representation as a model
• Developments in scientific research follow improvements in apparatus
• Discuss this statement with regard to the use of electricity and magnetism in Thomson's experiments with cathode rays
• In many textbooks the electronic configuration for vanadium is written as [Ar]4s23d3
• Suggest why this way of writing the electronic configuration for vanadium may be at odds with experimental evidence
• Hypothesis


  A tentative explanation that can be tested through investigation and exploration
• Theory


  An established array of ideas or concepts which may then be used to make predictions
• Inductive reasoning


  1. Observation

  2. Pattern

  3. Hypothesis

  4. Theory