C8 Flashcards
how do you calculate the rate of a reaction at a specific time
calculate the gradient of the curve of a graph drawn from an experiment testing how many reactants are used up over a period of time
how can you find out reaction rate
how quickly the reactants are used up as they make products or
how quickly the products of the reaction are made
what is the equation for mean rate of reaction
quantity of reactant used / time
quantity of product formed / time
what 5 main factors affect the rate of reaction
temperature surface area (solids) concentration (solutions) pressure (gases) presence of a catalyst
what is collsion theory
reacting particles have to collide with enough energy to cause a reaction to take place
what is activation energy
the minimum amount of energy that particles must have before they can react
what can you increase to make a reaction more likely
frequency of reacting particles colliding with each other
energy they have when they collide
why does powder have a faster reaction rate than a large lump of solid in a solution
powder has a larger surface area and each tiny bit is surrounded by solution whereas with a lump of solid only the outer particles are surrouded by solution
what are catalysts used in the form of and why
powders, pellets or fine gauzes as they then have the biggest surafce area : volume ratio
how do catalysts speed up a reaction
by providing an alternative reaction pathway to the products, with a lower activation energy than the reaction without a catalyst present so frequency of effective collisions speeds up
what are advantages of catalysts
they are cheaper than it would be to increase the temperature or pressure and they don’t use fossil fuels like temperature increasing would
also doesn’t get used up so can be used repeatedly
how can a catalyst eventually not work anymore
they become poisoned because impurities in the reaction mixture combine with the catalyst and stop it from working
