Chapter One chemistry note

·         Volume is the amount of space a substance occupies

·         Mass is a measure of the quantity a material contains; weight is a measure of the gravitational pull of an object

·         Metric system uses Liters and Grams for volume and mass

·         Measured numbers are ones obtained from using a tool

·         Exact numbers are counted or those by definition

·         All numbers are significant figures except for zero when it’s used at the beginning of a decimal (0.004 = 1 sigfig) or used as a place holder in a number with no decimal point (850,000 = 2 sigfigs)

·         Conversion factors:  Given # X unit for answer/metric factor to cancel initial unit = answer in desired unit

·         The ratio of parts per million indicates mg per kg; parts per billion indicates mcg/kg

·         Density = mass/volume; differences will determine whether the object will sink or float

·         When a solid is completely submerged, it displaces a volume of water that is equal to its own volume

·         Specific gravity is a ratio between a density of a substance and the density of water; density of sample/density of water = specific gravity**this is one of the few unitless values in chemistry