Chemistry Chapter 3 Scientific Measurement

Measurement

A quantity that has both a number and a unit

Scientific Notation

A given number is written as the product of two numbers

Precision

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

Accepted Value

The correct value based on reliable references

Experimental Value

The value measured in the lab

Error

The difference between the experimental value and the accepted value

Equation for Error

Error= experimental value-accepted value

Percent Error

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

Significant Figures

All of the digits that can be know precisely in a measurement, plus a last estimated digit

International System of Units

(abbreviated SI, after the French name, Le Systeme International d' Unites) is a revised version of the metric system

The Five SI base units commonly used by Chemists

Meter, Kilogram, The Kelvin, the Second, and the Mole

Meter (m)

The basic SI unit of length or linear measure, all measurements of length can be expressed in this

Liter (L)

The common unprefixed unit of volume in the metric system

Metric Units of Length

Kilometer (km)
Meter (m)
Decimeter (dm)
Centimeter (cm)
Millimeter (mm)
Micrometer (um)
Nanometer (nm)

Metric Units of Volume

Liter (L)
Milliliter (mL)
Cubic centimeter (cm)

Kilogram (kg)

The basic SI unit of mass

Metric Units of Mass

Kilogram (kg) (base unit)
Gram (g)
Milligram (mg)
Microgram (ug)

Weight

A force that measures the pull on a given mass by gravity

Temperature

A measure of how hot or cold an object is

Celsius and the kelvin

Scientists commonly use these two equivalent units of temperature

0 degrees Celsius 100 degrees Celsius

The Celsius Scale sets the freezing point of water at ___ and the boiling point of water at _____

273.15 kelvins 373.15 kelvins

On the Kelvin Scale the freezing point of water is ______ kelvins (K) and the boiling point is ____

Absolute zero

0 K or -273�C

Energy

The capacity to do work or to produce heat

joule (J)

The SI unit of energy

calorie (cal)

The quantity of heat that raises the temperature of 1 g of pure water by 1�C

Conversion factor

A ratio of equivalent measurements

Dimensional analysis

A way to analyze and solve problems using the units, or dimensions,of the measurements

Density

The ratio of the mass of an object to its volume

Intensive

Density is a(n) _________ property that depends only on the composition of a substance, not on the six of the sample