Chapter 1.5: Units and Conversion Factors in Calculations

Flashcards from Chapter 1.5 of Chemistry: The Molecular Nature of Matter and Change.

Conversion factors

Ratios used to express a quantity in different units

Dimensional analysis

The use of conversion factors in calculations, as units represent physical dimensions

• Requires units in all calculations

• Must cancel all units except those wanted in the answer

Exponentiated units

Requires that both the number and unit be raised to power when dealing with raised units

Density (d)

The mass of a substance divided by its volume; this is a constant value at a given temperature and pressure

• Measured in kg/m³ for SI, g/L or g/mL for chemistry

• Much lower for gases

Extensive properties

Properties dependent on the amount of substance present, like mass and volume

Intensive properties

Properties independent of the amount of substance, like density

• Ratios of extensive properties in this case remain the same