Chapter 14: Experimental Chemistry

Qualitative

does not involve number

quantitative

involves numbers

accuracy

measure value vs. true value

precision

closeness of repeated measurements

significant figures

precision of a measured number

absolute uncertainty

uncertainty of last digit of measurement

relative uncertainty

absolute uncertainty divided by number itself

independent variable

determined by experimenter

dependent variable

measured property of the independent variable

“TD” glassware

“to deliver”, most accurate for pouring

“TC” glassware

“to contain”, should not be used for pouring, only holding

stockpot

part of buret that controls flow of water

pycnometer

determines liquid density

specific heat equation

q = (mass)(specific heat)(temperature change)

bumping

sudden, violent burst of boiling

volumetric flask

used for obtaining specific volume of molar concentration

pneumatic troughs

collect gasses formed in a reaction

filtration

used to collect larger solids from a liquid

centrifugation

used to collect small solids from a liquid

supernatant

clear liquid from a centrifuge

distillation

separates liquids with two different boiling points

pH meter or pH paper

used to find specific pH

litmus paper

determines if solution is acidic or basic

spectrophotometer

measures amount of light that a colored solution absorbs

beer’s law

A = abc