Chemistry 1020--Lecture 2—Notes:

Recap:

Composition of air:

Nitrogen, Oxygen, Argon (elements)

Carbon Dioxide, Water vapor (compounds)

Pollutants, Less than 1%

Carbon monoxide, ozone,

sulfur oxides and nitrogen oxides

--express in ppm (parts per million)

Chemical properties: Neither Nitrogen nor Carbon dioxide support combustion (candle flame)

Demos:

CO₂ quenching candle flame

Oxygen--burning splint.

Balloon ignition: helium versus hydrogen. (nitrogen?)

End with hydrogen-oxygen mixture.explosion

Discuss phlogiston theory and discovery of oxygen.

To put these things in context, need to define some terms and develop some classifications. This may be old hat to most of you if you’ve had chemistry before, but be patient so we are all "on the same page".

Matter:

Mixtures: (variable composition)

Homogeneous (uniform throughout) SOLUTIONS

Heterogeneous (not uniform throughout)

Pure Substances (fixed composition)

Elements

Compounds

Two definitions: Operational and Theoretical

Elements

There are 109 known elements. Only about 90 occur naturally. The rest have been made artificially.

One of the major breakthroughs in chemistry was the organization of the elements in a periodic table.

Use web to show some periodic tables to obtain information on individual elements. Discuss symbols and names. Discuss organization into families.

While on the web, go through other items in the web site.

Web MC site

Chemweb site

Chemistry in Context site

Naming. Discuss names and origins

Diatomic elements (H₂, O₂, N₂, F₂. Cl₂, Br₂, I₂)

Allotropes (ex. O₂ and O₃; diamond and graphite)

Families

(metals and non-metals; alkali metals, alkaline earth metals, chalcogens, halogens, transition metals)

Next:

Compounds--naming--molecular formulas

Chemical equations