Results:The sodiumhydroxidegained weight and thesodiumcarbonatelost
weight.Therewas also adistinctchange in theappearanceofbothchemicals.
Why did these changesoccur?
The sodium carbonatelost weight because it lost its waterof hydration
throughevaporation.Thesodiumhydroxidegained weight because itabsorbed
water from the air.Howdo youthinkthisinformationcould beputtopractical
use?Remember,lossofwater is efflorescence and gainofwateris deliquescence.
Thereare many drugs, textiles,commercialchemicals, evensubstancesin the
basementsofhomes and summercottagesthatare affected by the presenceof
moisturein the air.Youhaveprobablyseenclothingbecome mildewedand
medicines become spoiled by too much or toolittle moisture.This is where
knowledgeofefflorescence and deliquescence can beputto use.Drugmanu-
facturers, for example, can keepmoisturein the air oftheirstockroomsby
exposing efflorescent chemicals. Ina summerhome, yourparentscanprevent
thefurnitureand clothingfrom being spoiled bydampnessby exposing deli-
quescentchemicals. Onedeliquescentchemical isparaformaldehyde(CH 20 2).It
is a big wordbutit can save a lot of money.
HOWYOUCANGROWACRYSTALGARDEN
Gather these materials: Sodiumsilicate (Na2SiOa) ;cobaltchloride(CoCI 2 ) ;
coppersulfate(CuS0 4 ) ;manganoussulfate(MnS0 4 ) ;leadnitrate(Pb(NOa) 2) ;
ferrous sulfate(FeS0 4 ) ;a glass pie pan or shallow bowl; an 8-inchlengthof
rubber tubing;a beaker;and water. Ifyou shouldhave difficulty in getting
any of these chemicals, ask yourdruggistfor any metallic salts thatform
coloredcrystals.
Follow this procedure:Inthe shallow pan, mix 1 cup ofsodiumsilicate with