Scientific notation

Examples of Scientific notation in the following topics:

• Scientific Notation

  • Scientific notation is a more convenient way of writing very small or very large numbers.
  • When writing in scientific notation, only include significant figures in the real number, "a."
  • Therefore, our number in scientific notation would be: $4.56 \times 10^5$.
  • Scientific notation enables comparisons between orders of magnitude.
  • Learn to convert numbers into and out of scientific notation.

• Significant Figures

  • Any numbers in scientific notation are considered significant.
  • When converting from decimal form to scientific notation, always maintain the same number of significant figures.
  • For example, 0.00012 has two significant figures, therefore the correct scientific notation for this number would be 1.2 x 10-4.

• Electrochemical Cell Notation

  • Cell notation is shorthand that expresses a certain reaction in an electrochemical cell.
  • Cell notations are a shorthand description of voltaic or galvanic (spontaneous) cells.
  • If the electrolytes in the cells are not at standard conditions, concentrations and/or pressure, they are included in parentheses with the phase notation.
  • Using these rules, the notation for the cell we put together is:
  • Produce the appropriate electrochemical cell notation for a given electrochemical reaction

• Curved Arrow Notation

• Formulas Using Other Configurational Notations

• Fischer Projection Formulas

  • The wedge and hatched line notations we have been using are effective, but can be troublesome when applied to compounds having many chiral centers.
  • As part of his Nobel Prize-winning research on carbohydrates, the great German chemist Emil Fischer, devised a simple notation that is still widely used.
  • Using the Fischer projection notation, the stereoisomers of 2-methylamino-1-phenylpropanol are drawn in the following manner.
  • The usefulness of this notation to Fischer, in his carbohydrate studies, is evident in the following diagram.

• The Building-Up (Aufbau) Principle

  • A special type of notation is used to write an atom's electron configuration.
  • The notation describes the energy levels, orbitals, and the number of electrons in each.
  • Using standard notation, the electron configuration of fluorine is 1s22s22p5.

• Stereochemical Notations

  • Since these configurational change notations are not appropriate for pericyclic reactions, new designations are needed.
  • A different notation for configurational change is required for electrocyclic reactions.

• Balancing Nuclear Equations

  • An example of this notation follows:
  • Instead of using the full equations in the style above, in many situations a compact notation is used to describe nuclear reactions.

• Cycloaddition Reactions

  • These notations are illustrated in the drawing on the right.
  • Also note that the pi-subscript is often omitted from the [m+n] notation for the majority of cycloadditions involving π-electron systems.