Chemistry - Chapter 2 Analyzing Data (copy)

base unit

a defined unit in a system of measurement that is based on an object or event in the physical world and is independent of other units

density

the amount of mass per unit volume; a physical property

derived unit

a unit defined by a combination of base units

kelvin

the SI base unit for temperature

kilogram

the SI base unit for mass

liter

the metric unit for volume; equal to one cubic decimeter

meter

the SI base unit for length

second

the SI base unit for time

conversion factor

a ratio of equivalent values used to express the same quantity in different units; is always equal to 1 and changes the units of a quantity without changing its value

dimensional analysis

a systematic approach to problem solving that uses conversion factors to move from one unit to another

scientific notation

expresses any number as a number between 1 and 10 (known as a coefficient) multiplied by 10 raised to a power (known as an exponent)

accuracy

refers to how close a measured value is to an accepted value

error

the difference between an experimental value and an accepted value

percent error

the ratio of an error to an accepted value

precision

refers to how close a series of measurements are to one another; precise measurements show little variation over a series of trials but might not be accurate

significant figure

the number of all known digits reported in measurements plus one estimated digit

graph

a visual display of data