C8 - Rate , equilibirum and organic chemistry Flashcards
What is the word equation for the practical about concenntration affecting rate of reaction with soidum thiosulfate solution .
Sodium thiosulfate solution +hydrochloric acid arrow sulfur (solid)
what is the product of the soidum thisoulfate solution , what state of matter is it in .
it i sulfur , sulfur is a solid .
what makes the solution is the practical go cloudy , wwhat do scientists call this ?
The sulfur makes the solution go cloudy , scientists call this turbidity .
method for the concentration practical - sodium thiosulfate
(recite from page )
is the sodium thisofulte souliton pracitcal reporucable
different people have different eyesights so some people may see the cross longer thn others so may not get the same results .(however is same size cross )
what is the second method for rp for concentration w magnesium word equation?
magneisum +hydrochloric acid arrow magnesium chlrodie and hyrdogen .
- Support a gas syringe with a stand, boss and clamp.
- Using a measuring cylinder, add 50 cm3 of dilute hydrochloric acid to a conical flask.
- Add a 3 cm piece of magnesium ribbon to the flask. -Immediately connect the gas syringe and start a stop clock.
- Record the volume of gas produced every 5 seconds.
- Continue timing until no more gas is given off.
- When the reaction is complete, clean the apparatus as directed by your teacher.
- Repeat steps 1 to 5 with different concentrations of hydrochloric acid.
what does the magnesium rp for concetrtaion produce , what are we masuring .
hydrogen gas . so it allow us to measure the volume of hyrdogen gas produced .
what do both experiments for concentration show
show that the greater the concentration of a chemical in a reaction , the faster the reaction tkes place .
with both methods for rp on concentration is this finding reporudcible why ,
the finding is reporcuuible as the result is shown by two different experiments .
what does collison theory say
collion thoery says that chemical reactions can only take place when the reacting particles collide with eachotehr . The collisons must hve sufficent energy .
how is the rate of a chemical reaciton determined
by the frequency of sucessful collisons .
what is frequency
the number of sucessful collisons per secod .
on the effect of concentraiton page on star 1 what does it show and why , what abt the colliosns
reactions are rapid innitially because we have a large number of reactant molecules .
so have a large number of colliosns per second
what does the second star show , why and collisons
overtime reactions slow down because the numbe rof reactant molecules arw runnning out .
Meaning smaller amount of colliosn per second .
What does the third star show , why and collions
finally the reaction sotps because all of thre reactan tmolecules hve ran out .
This means the number of collisons per second is zero .
if the concentration of particles is doubel what does it mean in terms of collion
double the collisons
what can we say if the rate of reaction increases as we increase the concentration
that rate is proprotional to the conentrtion
look at the graph on concenrtation , how can we tell the higher concentration is a fadser reaction
as it is steeper than lower concentrationof reactant
look at the graph , how can we tell that the higgher concentration gets more product at the end
as we started ewith more reactatnt molecules at the start than the lower concentraiton reactant .
RECAP - what happens to the particles if the concentration is increases
more particles in the same volume
RECAP - collison theory if we increase the concentratoin
particles collide more frequenlty
RECAP-what happens to the rate of reaction if we increase the concentration ?
it increases
what do smaller sized blocks have compared to larger sized blocks (surface area ) what does this mean ?
smaller sized blocks have a greter surface area to bolume ration thn larger blocks.
This means they have more particles in the same surface , so there are more colliosns per second increasing the rate of reaciton .
What are the two practicals for surface area .
meausre the volume of co2 gas
measure the amount of co2 lost .
an explanaiton of measuring the volume of c02 practical surface area
Put ten cmcubed of hydrochlic acid into concial flask . Add calcium carbonate chips
marble chips contain the chemical calcium crbonae .
This reacts hydrochloric acid to produce carbondioxide gas which goes thorugh a delivery tube and into a measuring cylilde in a trough of water .
We can measure the volume of co2 gas and use this to determine the rate of reaction .
We can then change the surface area of the marble chips .
why migh measuring the volume of c02 in cylidner be noto accurate , what can we use instead?
measuring in a cylinder is two difficult as the bubbles are quie rpid . So use a gas syringre for m ore accurate results .
an explatioN for the amount of co2 lost practIal ,
as carbondioxide is produced the mass decreases .
Can use this to calculate the raete of reaction .
cotton wool allows the gas to escape ,
However , cotton wool also prevents acid from splashing out of the flask . If any acid did splash out , it would cause the mass to fall more than it should producing an ANOMALOUS RESULT .
what is the activation energy
is the minimum amount of energy that the particles mist have in order to react (collide succcessfully )
what happens to the rate of reaction if we increase the temperature
it increases
what happens to the partciles if we increase temperature
particles have enegry greater than the reaction energy .
collison thoery when increasing the temperature in a reaction
particles with the activaiton energy collide more frequenlty .
what can we sya as the rate of reaction increases with temperature
the rate of reaction is proportional ot temperature till certain point , then hs no effect
what are catalysts ?
catalysts increse the rate of chemical reactions but are not used up during the reaction .
what are the advanatges using catalysts ?
catalysts allow us to carry out reactions quickly wihot needing to increase the temperarue saving money .
what can we do as catalysts re not used up
reuse them again and again
catalysts - look at the graph - what does the rate of reaction depend on
the rate of reaction depends on the n umber of particles that have enough energy to cross the activtion energy barrier and collide succesfully .
how do catalysts increase the rate of reaction
catalysts increase the rate of reaction by providing a ddifferent pathway for the reaction that has a lower activation energy .
SUM UP - how does a catalyst increase the rate of reaction (4m)
when a catalyst is present , the particles rewuire less energy to cross the activation energy barrier .
This mens that more particles can successfully collide per second .
Increasng the rate of reaction .
why do we not include catalysts in the chemical equation for a reaction ?
As catalsts are not used up in a reaction . Catalysts are not a reactant
what are biological catalysts called
enzymes
what do all different reactions nee (enzymes)
different enzymes
SUM UP -how does increasing the temperature increase the rate of reaction ? (4m)
Increasing the temperature increases the rate of chemical reactions as the particles have more nergy , thye move faster , this increases the frequency of collions (gretaer number of collisons per second ) .Each collison now has more energy to overcome the acitvation energy barrier and collide successfully .
SUM UP - how does increasing the surface area increase the rate of reaction (4m)
increasing the surface area , increases the number of available particles , particles collide more frequenlt with activation energy , increasing the rate of reaction .
SUM UP - how does increasing concentration increase the rate of reaction (4m)
increasing concentration means there are more particles in thsame volume , so particles collide more freuqnlty increasing the rate of reaction
what is an open system
where substances can enter ot lrrsvrleave
what is a closed system
where substances cannot enter or leave (bung in )
in equilibrium do reactions still occur
yes reactions are still occuring
what happens in an exothermic reaction , what happens to the temperature .
transfers energy to the surrounds , the temperature of the surroundings increases
what happens in endothermic reactions , what happens to the temperature .
absorbs energy from the surroudings and the temperature of the surroundings ddecreases .
what is dynamic equillibrium
when the rate of the forward reaction equals the rate of the reverse reaction .
check your page oon effect of changing concentration on equilibrium , what happens if we increase the concentration of NO2
The concentration of reactions to produts is no longer at equilibrium .
The foreard and reverse reactions are not taking place at the sae rate
so the concrations of all the subsatcnes will change into equilibrium is reached . IN THIS CASE , increasing the cocnentraion of NO2 m ore N2O4 will be formed until equilibirum is reached .
(look t equilibirum sheet ) what will happen if we decrease the concentration of N204
Because we have decreased the concentration of N204 , the system is no longer at equilibrium .
More NO2 will react to form N204 util the equilibrium is reached again .
What would happen if we increase the concentration of N204 (look at equilibrium sheet )
As we increase the concentratgion of N204 , the system is no longer at equilibrim .
More N204 will turn into NO2 until equilibirum is reached again .
(changing temp sheet example ) in the reaction , the forward reaction is exothermic , what does this mean ?
It means that energy is released and the temperature of the system increases .
what does it mean if the reaction is exothermic one way
it is endothermic the other .
(changing temp sheet example ) what is the reverse reaction and what does this mean
Reverse reaction is endothermic , meaning when the reverse reaction takes place , energy iss taken in and the temperature of the sysem decreases .
changing temp sheet example ) what happens if we increase the temperature of this system
the equilibrium will shift ot the left to reduce the temperature .
Reverse reaction is endothermic so energy is taken in cauing the temperature to fall .
So the amount of NO2 Would increase , and the amount of N204 would decrease ,
(changing temp sheet example )What would happen if we decrease the temperature of this system
Equilibrium iwll shift ot the right to increase the temperature ,
As the forwardd reaction is exothemric , so the enrgy is relased causing the temperature to increase
IN THIS CASE , the amount of N204 would increase and the amount of NO2 would decrease .
what type of moleucles does pressure affect
reactions involivng gases .
What does the pressure of a gas depend on
the number of molecules
(check pressure sheet ) which container has more pressure left or right
the right
what happens to the equilibrium if you increse the pressure on a reversible reaction
the equilibrium shifts to the side with the smaller nuber of moecules .TO minimise the affect .
what happens to the equilibrium if you decrease the pressure on a reversible reaction
then the position of the equilibrium shifts to the side with thelarger number of molecules .
(check pressure sheet ) what happens if we increase the pressure of the equilibrium for example EXPLAIN
The equilibrium iwll move to the right hand side as the right hand side has fewer molecules than the left .
(check pressure sheet ) what happens if we decrease the pressure of the equilibrium for example EXPLAIN
if we reduce the pressure on the reaction , the equilibrium will shift to the left hand side as the left hand side has more molecules than the right/
In terms of pressure , what happens to the equilibrium if both sides of the equation has the same number of mollecules ?
changing the pressure has no effect on the position of the equilibirum ,
What hppens if we heat hydrated copper sulfate , what does this reaction produce .
it reacts to form anhyrdrous copper sulfate which is white . This reaction also produces water .
what type of reaction is it if we heat hydrated copper sulfate , how can you tell ?
as we are heating it , we are putting energy in , this tellus us that the forward reaction is ENDOTHERMIC .
how do we do the reverse for the anhydrous copper sulfate reaction .
if we take our anhyrdous copoper sulfate and add water , the reaction is reversed .
what type of reaction is the reverse reaction for anhydrous copper sulfate , how do we know
in the reerse reaction , energy is released , the reaction gets hot . This tells us the reverse reaction is EXOTHERMIC .
