Element - a substance that can't be broken down into a simpler substance

Ex) Na, Si, H_2,, S₈

Compound - a substance composed of more than one element

Ex) CO₂, NaCl, NaHCO₃

Pure Substance - any single element or any single compound

Mixture - A combination of more than one substance (element and/or compound)

Homogeneous Mixture - A mixture with uniform composition

Ex) Air, salt water (unsaturated solution)

Heterogeneous Mixture - A mixture lacking uniform composition

Ex) Paint, oil/vinegar salad dressing

Chemical Change - a change that involves the conversion of at least one substance into a different substance

Physical Change - a change in which no substances are converted into different substances

Intensive Property - -A property independent of sample size

Ex) Melting point, boiling point, density

Extensive Property - A property dependent upon sample size

Ex) Mass, volume

Precision - Of or relating to how close multiple measurements of the same value are to each other (independent of how close they are to the true value)

Accuracy - The degree to which a measurement corresponds to the ‘true’ value.