1. Energieverandering in reaksies (eksotermies en endotermies
Wanneer ons na die energie- of hitte-oordrag in ’n chemiese reaksie kyk, gesels ons oor
termodinamika.
Wanneer die suiker in jou liggaam met suurstof reageer, vorm energie. Hierdie energie kan
vir baie verskillende dinge gebruik word.
Verskillende chemiese reaksies kan of energie vrystel of opneem om te gebeur.
Hierdie verskil in die energie voor die reaksie en na die reaksie staan bekend as
reaksiewarmte (ΔH). Dit is dan die netto verandering in die potensiële energie van die
sisteem.
Sekere sisteme stel energie vry. Hierdie tipe reaksie staan bekend as eksotermiese reaksies.
Dit is dan reaksie wat potensiële energie oordra na termiese energie.
Die ander tipe reaksie benodig weer energie om plaas te vind. Dit staan dan bekend as
endotermiese reaksies. Hier word termiese energie oorgedra na potensiële energie.
ΔH word ook beskryf as entalpie.
ΔH = Eprodukte - Ereaktante
Wanneer energie dan by ’n sisteem gevoeg word, kry die hele sisteem meer energie. Dus,
tydens ENDOTERMIESE REAKSIES, sal die produkte meer energie as die reaktante hê. Net
omdat dit energie bykry, beteken nie dit word warm nie. Dit gee hitte af as dit energie
verloor. Dus tydens Endotermiese reaksies: ΔH > 0
Wanneer ’n sisteem dan energie verloor, het die produkte minder energie as die reaktante.
Die hitte wat jy voel, beteken die produkte het die energie weggegee, dus tydens
Eksotermiese reaksies: ΔH < 0
Wanneer ons dan molekules moet vorm, dus bindings tussen die molekules moet vorm, dan
is die reaksie eksotermies.
Wanneer ons molekules moet afbreek, dus bindings breek tussen molekules, dan is die
reaksie endotermies, want ons voeg energie by om die binding te breek.
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