THE LANGUAGE OF CHEMISTRY
By the time you are oldenoughto read this bookyou will surely have heard
people using words like these: atom,molecule, element and compound.You
may know what some of them mean, butothersmay seem too difficult to
worryabout.You may have seen somestrangecombinationsofnumbersand
letters,too,like those shown here, andwonderedwhatin the world they could
mean:
2NaHCOa+H2S0 4-+2C0 2 +2H 20 +Na2S
This is thelanguageofchemistry. Before you begin to learn thislanguage,
there is one veryimportantthing to know. All of science is based on lawsof
nature,and the lawsofnatureare basically simple anddependable.If you let
goofa rock you areholding,it will fall to theground.If water gets coldenough,
it will freeze. If you add 2 and 2correctly,you will always get 4. The sun always
rises in the east and sets in the west. These are lawsofnature;we candepend
uponthem.Couldanythingbe more simple or moresatisfying?
Chemistry,like all the physical sciences, is based on laws ofnaturetoo.
When the sameatoms(the smallest whole particles ofmatter)orcombinations
of atomscome together under the samecircumstances, the same chemical
reactions always take place. Time after time, chemists have found molecules
(smallgroupsofatomsboundtogetherchemically) behaving in exactly thesame
way, whenconditionsgoverning them are the same.
Nowlet's try tounderstandthislanguageofthe chemist.Atomsand mole-
cules are not alwayssynonymous;butincertaincases they are. Anatom,by
itself, is a singleunit,so anatomcannotbe made any simpler, exceptunder
exceptionalcircumstances.A molecule may consistofoneatomor morethan
one.Thusit can often be made simpler.
Chemistshave agreed on asortof scientificshorthandin which lettersstand
for the names ofelements, substancescomposedofonly one kind ofatom.
They call these letters chemical symbols.Combinationsofsymbols represent
the different atomsin aparticularkindofmolecule. Thesecombinationsare
calledformulas, and they show what elements arecontainedin acompound.
Acompound,as you can probablytell, is asubstancemade up ofmolecules