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26 Cards in this Set
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Define rate of reaction? 
how fast a chemical change is takign place in terms of how fast reactants are removed or how fast products are formed in a given time 

Rate of reaction equation? 
Rate= Change in concentration of reactants or products/ Time 

Units of rate of reaction? 
moldm3 s1 

What must be stated with any result when measuring rate of reaction and remain constant? 
Temperatureit's value must be stated and recorded 

Give 6 examples of how to meausre the rate of reaction 
1) Volume of gas produced (gas syringe or water displacement) 2) Mass decrease when gas is evolved (balance) 3) colour intensity change (colorimetry) 4) pH when acids or alka;os are involved: pH probe and meter 5) Stop reaction at intervals and titrate each time (quenching) 6) Conductivityions produced/used 

What is the shape of a concentration time graph for a reaction of order? 
a negative gradient (straight line) ( due to reaction rate being constant) 

What is the shape of the concentrationtime graph for a overall reaction of 1st order? 
Negative gradient decreases gradually over time (due to reaction depending on reactant concentraion) 

What shape is the concentrationtime graph for a second order reaction comapred to a first order reaction? 
Second order had a much more steeper curve than first order 

Define half life 
The half life of a reactant is the time it takes foor it's concentration to reduce by half 

What is the rule for the half life of first order reactants? 
'If a reaction is 1st order with respect to a reactant, then the halflife is constant and independent of the concentration 

What happens to half life of 0 order reactant? 
decreases over time 

What happens to half life of 2nd order reactant? 
Increases over time 

What is the shape of a reaction rateconcentration graph for a 0 order reactant? 
Straight line, no gradient 

What is the shape of a reaction rateconcentration graph for a 1st order reactant? 
A straight line through the origin ( reaction rate is directly proportional to concentration of reactant) 

What is the shape of a reaction rateconcentraion graph for a 2nd order reactant? 
Expotentially increases (reaction rate is directly proprotional to concentration of the reactant SQUARED) 

Describe intitial rates metod 
Several different experiments are carried out, where in each separate experiment the initial reaction rate is estimated for one different initial reactant concentration with all other variables unchanged 

What is approximately true about the the initial rate of reaction? 
The rate of reaction is constant 

Equation of initial reaction rate is: 
[reactant] (initial)  [reactant] (t) / time,t 

What was the clock reaction? 
Initial rate is appromiately directly proportional to 1/t If total volume was kept constant, the solution used with be proportional to it's concentraion 

what is the rate determining step in a reaction mechanism? 
The slowest step and controls how fast the reaction proceeds 

How can you determine the order of reactants from the rate determining step? 
'The number of each chemical species reacting in the rate determining step equals its orderin the rate equation' 

What happens to the Rate constant (k) when temperature increases? 
Rate constant is only constant at constant temperature; k increases dramatically (exponentially) when temperature increases and therefore so does rate 

What does the Arrheuis equation show? 
Shows the exponential relationship between the rate constant K and absolute temperature T (in kelvin) 

In the data book, what form is the Arrheuius equation in? 
y = mx + c 

What is the equation to work out Activation energy? (Ea) 
Ea =  (m (gradient) x R (Gas constant) 

What is the equation to work out A (frequency of successful collisions)? 
e c (to the power of cwhich is the intercept) 