The Rate And Extent Of Chemical Changes Flashcards
(19 cards)
what is a catalyst
a substance that increases the rate of a chemical reaction without being used up in the reaction
catalysts are not included in the …
chemical equation for the reaction
what energy does catalysts reduce
the activation energy
what does a catalyst do to a reaction
speeds it up
what does a catalyst provide
a surface for the molecules to attach to which increases their chance of colliding
Enzymes act as a catalyst …
in biological systems
different reactions need …
different catalysts
in a closed system no reactants are …
added
in a closed system no products are …
removed
when a reversible reaction occurs in a closed system ..
an equilibrium is achieved
define equilibrium
a state where the rate of the forward reaction = the rate of the backwards reaction
what does the relative amounts of all the reacting substances at equilibrium depend on
rhe conditions of the reaction
what is Le Chatelier’s principle
if a system in equilibrium is subjected to a change in conditions then the system shifts to resist the change
in an exothermic reaction if temperature increases ..
yield decreases
in an exothermic reaction if the temperature decreases ..
yield increases
in an endothermic reaction if temperature increases …
yield increases
in an endothermic reaction if temperature decreases ..
yield decreases
in reactions involving gases an increase in pressure favours …
the reaction that produces the lowest number of gas molecules
what 2 things happen about equilibrium if the concentration of one of the reactants or products is changed
system is no longer in equilibrium
system adjusts until it can reach equilibrium once more
