A2 Unit F325 - Equilibria, Energetics and Elements
Samenvatting
Summary Chemistry A Level OCR
9 keer bekeken 0 keer verkocht
Vak
A2 Unit F325 - Equilibria, Energetics and Elements
Instelling
OCR
This slide show consists of all the topics and sub - topic the OCR exam board requires in only 76 slides.
Slides are straight to the point using key terminology which is exam specific.
Slides only take about 5 minutes to read saving you time and energy.
A2 Unit F325 - Equilibria, Energetics and Elements
Alle documenten voor dit vak (40)
Verkoper
Volgen
20arpanahim
Voorbeeld van de inhoud
CHEM
YEAR 2
, ORDER OF REACTION
This is the exponent/number which describe the change in conc effect on initial rate of reaction
Sometimes increase in conc does not increase rate
0 order- conc has no effect - straight line across y axis
1st order - directly proportional conc and rate increases by the same number - straight line - y=mx+c line
2nd order - exponential if conc doubles rate gets squared shown by a exponential model graph- curved
2nd order - e.g. - if you triple conc rate of reaction increases by 3 squared (9) and etc
Overall sum of orders is when you just add the orders in a reaction together
Finding orders of reaction Finding order of initial B
E.g. So 0.4/0.1 = 4
Initial rate was 0.8 which times by 4 = 3.2
Hence this is a directly proportional relationship and is the 1st order
Finding order of A - changes between 2 and 3
Account for B first - doubles between 2 and 3 hence 3.2 should double
without A being involved - so it becomes 6.4
However it becomes 1.6 with A hence it is smaller by a factor of 4
As 6.4 divided by 1.6 = 4
As A halves rate becomes smaller by ¼ hence it is an exponential
relationship - 2nd order
If you account for A and B you will see no change in initial rate of
reaction when C changes conc between 3 and 4 hence is 0 order
, CONC Vs TIME GRAPHS
Straight line is order 0 curved line is order 1 even more exponential/ curved graph is order 2
To find gradient of the curve you draw a tangent then do the conc/time
To prove orders of reaction you find the gradient at 2 separate points and then compare the relationships with
respect to conc and time - e.g. if one halves and the other halves as well it is first order
, HALF LIFE
Finding t ½
-choose any point on
y axis
This is the time taken for a conc of a reactant to decrease by half -half it
Used in various practicals to deduce the order -its difference in time
is its half life
How to work out half life from graph
Choose a conc - in this case e.g. 1.2
Half the conc
See what time it is at in this case 0.6 conc = 60 sec
Half the conc again - 0.3
At 0.3 it is at 30 sec
-As time is getting halved each time conc is getting halved this is 0 order
Half life is written as t ½ decreases over time
-For 1st order time stays the same as conc halves and is t ½ stays
constant
-For 2nd order as conc halves time doubles which is written as t ½
increases over time
Equation to find the rate constant, K, can only be used for overall order of a 1st order of reaction
Equation = ln2 / t ½
T ½ of course is the half life in seconds for 1st order this is constant always
Voordelen van het kopen van samenvattingen bij Stuvia op een rij:
√ Verzekerd van kwaliteit door reviews
Stuvia-klanten hebben meer dan 700.000 samenvattingen beoordeeld. Zo weet je zeker dat je de beste documenten koopt!
Snel en makkelijk kopen
Je betaalt supersnel en eenmalig met iDeal, Bancontact of creditcard voor de samenvatting. Zonder lidmaatschap.
Focus op de essentie
Samenvattingen worden geschreven voor en door anderen. Daarom zijn de samenvattingen altijd betrouwbaar en actueel. Zo kom je snel tot de kern!
Veelgestelde vragen
Wat krijg ik als ik dit document koop?
Je krijgt een PDF, die direct beschikbaar is na je aankoop. Het gekochte document is altijd, overal en oneindig toegankelijk via je profiel.
Tevredenheidsgarantie: hoe werkt dat?
Onze tevredenheidsgarantie zorgt ervoor dat je altijd een studiedocument vindt dat goed bij je past. Je vult een formulier in en onze klantenservice regelt de rest.
Van wie koop ik deze samenvatting?
Stuvia is een marktplaats, je koop dit document dus niet van ons, maar van verkoper 20arpanahim. Stuvia faciliteert de betaling aan de verkoper.
Zit ik meteen vast aan een abonnement?
Nee, je koopt alleen deze samenvatting voor €12,94. Je zit daarna nergens aan vast.
