ODWS icon

The Open Door Web Site
HOMEPAGE BIOLOGY PHYSICS ELECTRONICS HISTORY HISTORY OF SCI & TECH MATH STUDIES LEARNING FRENCH STUDY GUIDE  PHOTO GALLERY
CHEMISTRY HOMEPAGE VISUAL CHEMISTRY PHYSICAL SCIENCE LABORATORY WORK 

 

Tutorial Index

Introduction to Elements, Atoms, Molecules,
Compounds and Chemical Bonding

Introduction to Chemical Bonding
Metals, Non-metals and Compounds
Non-metal Radical Groups
Names of Acids and other compounds
Introduction to Chemical Reactions, the
Rules and the products of a reaction

Types of Chemical Reactions I
Types of Chemical Reactions II
Introduction to the Periodic Table
Balancing Chemical Equations

The Chapters Index

 

Using chemical formulae

 

Test Yourself
(Opens in a new window)

Exercise VIII
(Opens in a new window)

 

 

THE LANGUAGE OF CHEMISTRY

Custom Search

Using chemical formulae

We can use the chemical symbols to construct chemical formulae for the molecules and compounds we have met in the tutorials.

 

Image

Formula

Notes

molecule01

O2

A molecule of oxygen gas has two oxygen atoms chemically joined together. This is shown in the formula by the number 2 as a subscript.

molecule02

N2

As with oxygen gas, nitrogen gas is identified by the number 2 as a subscript in the formula.

molecule03

H2O

Water : When hydrogen appears in a formula it normally appears first (it is incorrect to write OH2 as the formula for water!).

molecule04

CO2

Carbon dioxide : The carbon atom is shown first in the formula (as it is in the name). Again, it is incorrect to write O2C as the formula for carbon dioxide!

molecule05

KOH

Potassium hydroxide: Remember that the hydroxide radical has one bonding arm.

molecule06

CuCO3

Copper II carbonate : The carbonate radical has two bonding arms. So does the copper atom, according to the name of the compound.

.

Image

Formula

Notes

molecule01

Na2SO4

Sodium sulfate : The subscript 2 indicates that two sodium atoms are needed to combine with one sulfate radical.

molecule02

Ca(NO3)2

Calcium nitrate : Notice that the nitrate radical has the formula NO3. When more than one is present in a compound the NO3 is placed in brackets () and the subscript number after the second bracket indicates the number of nitrate radicals present.

molecule03

HCl

Either hydrogen chloride gas or hydrochloric acid if it is in solution (dissolved in water).

molecule04

HNO3

Nitric acid : The correct name would be hydrogen nitrate but the old name has stuck!

molecule04

H2SO4

Sulfuric acid : The correct name would be hydrogen sulfate but, again, the old name is too well known and is more commonly used.

 

The Open Door Web Site is non-profit making. Your donations help towards the cost of maintaining this free service on-line.

Donate to the Open Door Web Site using PayPal

SITE MAP
WHAT'S NEW?
ABOUT

PRIVACY

COPYRIGHT

SPONSORSHIP

DONATIONS

ADVERTISING

© The Open Door Team 2017
Any questions or problems regarding this site should be addressed to the webmaster

© Shirley Burchill 2017

Hosted By
Web Hosting by HostCentric


SiteLock