Science 010 - Fall, 1995

Lecture 4 - Sept 26

Discovery and Some Chemistry of the Atmosphere

  1. Discovery of oxygen by Priestley

    Properties and reactions of oxygen. Uses of oxygen. Ozone: synthesis, structure, properties.

  2. Discovery and properties of nitrogen

    Uses of nitrogen. Ammonia synthesis.

  3. The noble gases and their discovery

    How could such unreactive elements be discovered?

  4. Carbon dioxide:

    Structure, reaction with water, acidic behavior. More of this when we do greenhouse effect. Sources of some other trace gases, eg., methane

  5. Some common "pollutants"

    Nitrogen oxides, sulfur dioxide. We will discuss these again under acid rain in a later lecture.

  6. Common Cycles

    a The common cycles that transfer elements between the atmosphere and organisms: nitrogen cycle, carbon cycle, oxygen cycle, sulfur cycle.

    Assignment for Lecture 4 - September 19

    1. Discrepancies in the experimental values of the molecular weight (molar mass) of nitrogen provided some of the first evidence for the existence of the noble gases. If pure nitrogen is collected from the decomposition of ammonium nitrite, it's measured molecular weight is 28.01. If O2, CO2, and H2O are removed from a sample of air, the remaining gas has an apparent (average) molecular weight of 28.15. Assuming this discrepancy is solely a result of the presence of argon (atomic weight = 39.95) calculate the ratio of the moles Ar to moles N2 in air. While we are at it, write the formula for ammonium nitrite and the equation for its decomposition, and suggest how you would go about chemically removing O2, CO2 and H2O from air.

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    Modified: 21/09/1995 by goddyn@sfu.ca (Luis Goddyn)