topic 7 rates of reaction and energy changes Flashcards
how do you calculate rate of reaction
amount of reactant used or amount of product formed/ time
how can you calculate rate of reaction using a precipitate reaction
mix the reactants and put the flask on a piece of paper with a cross on it, measure how fast it takes to be obscured, is subjective
how can you calculate reaction time of a reaction that produces gas
use a measuring scale to measure the change in mass, when it stops changing the reaction is finished although it could release harmful gas into the air
how can you measure rate of reaction using a gas syringe
measure amount of gas given off, you know the reaction has stopped when there is no more gas, but you could blow the plunger out the end
why do finer marble chips give a faster rate of reaction
because they have a larger surface area, more space for the reaction to occur
why does a higher concentration give a faster rate of reaction
more particles collide
what solutions do you use for the cross experiment thing
sodium thiosulfate and hydrochloric acid, gives off a sulfur precipitate
what happens to the rate of reaction when you increase the temperature
it gets faster
what is activation energy
the minimum energy that particles need to react when they collide
why does increasing temperature increase the rate of reaction
particles move faster so increases collision rate and energy of the collisions
why does increasing temperature increase the rate of reaction
particles move faster so increases collision rate and energy of the collisions
how do catalysts work
by decreasing the activation energy by providing an alternate reaction pathway
what is an example of a biological catalyst (enzyme)
yeast cells
what is an endothermic reaction
takes in energy from the surroundings usually in the form of heat, shown by a decrease in temp of surroundings
what is an exothermic reaction
gives out energy to the surroundings usually in the form of heat, shown by an increase in temp of surroundings
