Significant Figures

Examples of Significant Figures in the following topics:

• Significant Figures

  • For example, 91 has two significant figures (9 and 1), while 123.45 has five significant figures (1, 2, 3, 4, and 5).
  • The number 0 has one significant figure.
  • The last significant figure of a number may be underlined; for example, "2000" has two significant figures.
  • 1.423 x 4.2 = 6.0 since 1.423 has 4 significant figures and 4.2 only has two significant figures, the final answer must also have 2 significant figures.
  • Don't be confused by significant figures.

• Scientific Notation

  • When writing in scientific notation, only include significant figures in the real number, "a."
  • Significant figures are covered in another section.
  • Keep in mind that zeroes are not included in "a" because they are not significant figures.

• Exact Numbers

  • Exact numbers have an infinite number of significant figures, but they often appear as integers.
  • In contrast, measured numbers always have a limited number of significant digits.
  • On the other hand, because exact numbers are not measured, they have no uncertainty and an infinite numbers of significant figures.

• The Uncertainty Principle

  • So significant figures ARE important after all!

• Determining Atomic Structures by X-Ray Crystallography

  • The steps to the process of determining the three dimensional structure of a molecule are outlined in this figure.

• Properties of Nitrogen

  • Significant absorption occurs at extreme ultraviolet wavelengths, beginning at a wavelength of around 100 nanometers.
  • Nitrogen absorption leads to significant absorption of ultraviolet radiation in the Earth's upper atmosphere and the atmospheres of other planetary bodies.
  • The figure summarizes the major processes through which nitrogen is converted between its various forms on the surface of the earth.

• Phosphorus Compounds

  • Two DNA strands are shown in the figure.

• Writing Lewis Symbols for Atoms

  • The arrangement of the periodic table can help you figure out this information.
  • The significance in understanding the nature of the stability of noble gases is that it guides us in predicting how other elements will react in order to achieve the same electronic configuration as the noble gases by having a full valence level.

• The Effect of Intermolecular Forces

  • At high pressures and low temperatures, intermolecular forces between gas particles can cause significant deviation from ideal behavior.
  • The contribution of intermolecular forces creates deviations from ideal behavior at high pressures and low temperatures, and when the gas particles' weight becomes significant.
  • At high pressures, gas particles are forced into close proximity with one another, causing significant intermolecular interactions.
  • When the weight of individual gas molecules becomes significant, London dispersion forces, or instantaneous dipole forces, tend to increase, because as molecular weight increases, the number of electrons within each gas molecule tends to increase as well.
  • At high pressures and low temperatures, these attractive forces can become significant.

• Electrolysis of Water

  • Pure water cannot undergo significant electrolysis without an electrolyte, such as an acid or a base.
  • Pure water cannot undergo significant electrolysis without adding an electrolyte.