Chemistry Test Review

base unit

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

second

SI base unit for time

meter

unit of length

kilogram

SI unit for mass

derived unit

A unit defined by a combination of base units

volume

Amount of space occupied by an object

gram

unit used to measure mass

milliliter

Basic unit of volume in the metric system

length

meter (m)

temperature

A measure of the average energy of motion of the particles of a substance.

density

Mass per unit volume

Kelvin

SI unit for temperature

scientific notation

a method of expressing a quantity as a number multiplied by 10 to the appropriate power

conversion factor

a ratio of equivalent measurements

dimensional analysis

a technique of problem-solving that uses the units that are part of a measurement to help solve the problem

water displacement

a method used to determine the volume of an irregular solid

accuracy

how close a measurement is to the true value

precision

a measure of how close a series of measurements are to one another

percent error

the absolute value of the error divided by the accepted value, multiplied by 100%

significant figure

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

How many sig figs in 200?

1 sig fig

How many sig figs in 0.00430?

3 sig figs

How many sig figs in 560?

2 sig figs

How many sig figs in 400.?

3 sig figs

How many sig figs in 0.87090?

5 sig figs

Round to 2 sig figs: 9462

9500

Round to 3 sig figs: 0.008539

0.00854