Chemistry Chapter One Vocab

chemistry

study of the composition and properties of substances, and the changes that such substances can undergo

conclusion

judgement or opinion formed as a result of analyzing experimental data

conversion factor

fraction having a value of 1 that is written from a unit equality and is used to change a measurement from one unit to another

scientific method

orderly and systematic approach to gathering info in order to answer questions about the world

observation

fact that is noticed either qualitatively or quantitatively, usually as an early part of the scientific method

hypothesis

proposed, but unproved, explanation of observed facts

experiment

carefully devised procedure for making observations and gathering data

natural law

description of a phenomenon that has been repeatedly and uniformly observed in nature

theory

logical and time-testd explanation of a phenomeno that occurs in the natural world

variable

factor being tested in an experiment

metric system

decimal system of measurement used internationally; basic units in this system are the meter for length, liter for volume, gram for mass, and Celsius degree for temperature

SI

system of units that is an extension of the metric system; includes seven base units to measure length, mass, time, termperature, electric current, light intensity, and amount of a substance

base unit

one of seven units used in the International System of Units, including the meter, kilogram, second, mole, kelvin, ampere, and candela

mass

quantity of matter in an object

derived unit

unit in the International System of Units that results from a combination of base units

volume

amount of space that an object occupies

metric prefix

syllable or group of syllables attached to the beginning of a metric unit in order to make the unit larger or smaller

precision

measure of the agreement between the numerical values of two or more measurement that have been made using the same method

accepted value

standard value for a measurement

accuracy

indication of how close a measurement is to its accepted value

significant digit

digit in a measurement that is certain, plus one digit that is an estimate

percent error

relative error as determined by finding the difference between an accepted value and a measured value, dividing the result by the accepted value, and multiplying the quotient by 100 percent

density

mass of an object divided by its volume; can be used to identify a substance

dimensional analysis

technique for converting between units by using the numerical relationship between the units

unit equality

equation that shows the numerical relationship between two units