Chem 2

often used to express the concentration of commercial aqueous reagents.

specify the concentration of a solution prepared by diluting a pure liquid compound with another liquid.

expresses the mass of a sub- stance per unit volume. In SI units, density is expressed in units of kg/L or alternatively g/mL.

the closeness of a mea- sured value to the true or accepted value.

causes data to be scattered more or less symmetrically around a mean value.

causes the mean of a data set to differ from the accepted value.

differ from indeterminate and determinate errors. They usually occur only occasionally, are often large, and may cause a result to be either high or low. They are often the product of human errors.

Three types of systematic error

caused by nonideal instrument behavior, by faulty cali- brations, or by use under inappropriate conditions.

arise from nonideal chemical or physical behavior of analytical system

result from the carelessness, inattention, or personal limitations of the experimenter.