C6 Rates of reaction. Flashcards
what is a rate of reaction
how quickly the reactants form into the products
give an example of a slow reaction
iron rusting
give an example of a moderate reaction
magnesium reacting with acid
give an example of a fast reaction
burning
how does a reaction occur
particles colliding with high energy
what is activation energy
the minimum amount of energy required for a reaction to happen
Four variables that effect rate of reaction
temperature, pressure, surface area, catalyst
equation for rate of reaction
rate of reaction= mass of product/time taken
How do you record rate of reaction using colour change
in a transparent solution, you put your reactant in, and records the
time taken for it to cause a change in colour or disappear
how do you record rate of reaction using change in mass
you put the mixture on a balance and record, at intervals, the amount
of gas given of by the reduction in mass”
how do you record rate of reaction using volume of gas given off
you use a gas syringe to record the amount of gas given off
what do magnesium and hcl react to create
H2
describe the practical involving the reaction of magnesium and HCL
“HCL solution into a conical flask and onto a balance. add magnesium
along and then plug it with cotton wool. take readings of the mass at
regular intervals
how do you find the mean rate of a reaction using a graph
ychange/xchange
using a graph, how do you find a reaction rate at a specific point in the graph
draw a tangent and then do y change/ x change
in what system only, can an equilibrium occur
a closed system
describe an equilibrium
forward and backward reactions occur at exactly the same rate, in a closed system which causes the products and reactants to maintain the same concentrations.
What is le chatelier’s principle
that an equilibrium will counteract any changes made to it
using le chatelier’s principle, what will happen if an equilbrium gains heat
it will begin to give of heat
what does sodium thiosulfate and HCL react to produce
A sulfur precipitate
how would you investigate the effects of different concentrations of HCl/
sodium thiosulfate on the rate of reaction.
Add a set volume of sodium TS to a conical flask. place a black cross underneath it
and add some dilute HCL. Time how long it takes for black cross to disappear. repeat
for different concentrations of HCL/sodium thiosulfate to show how concentration
effects the rate of reaction.
what effect will a higher concentration HCl have in the sulfur experiment
It will increase the rate of reaction
why does higher pressure mean a faser rate of reaction
particles move faster. More collisions. this creates more energy for reaction to happen
What is the main cause of a faster rate of reaction
More collisions between particles
when answering a question on how the RoR increases, always explain how….
More collisions have occured
How does a catalyst increase the rate of reaction
speeds up the reaction without actually being used itself. decreases the activation energy
