Reaction rates

Question	Answer
Activation energy	the minimum energy which particles need to collide to start a reaction
Effect of Increasing Concentration and Increasing Pressure	At higher conc. and P there are more particles per unit volume Particles collide with a greater frequency there will be a higher frequency of effective collisions.
Na2S2O3 + 2HCl measuring rate	2NaCl + SO2 + S + H2O 1/time time is t for X placed underneath the reaction mixture to disappear due to the cloudiness of the Sulphur
Why is this an approximation?	it does not include concentration. We can use this because we can assume the amount of Sulphur produced is fixed and constant.
Effect of catalyst	Provide an alternative route or mechanism with a lower activation energy so more molecules have energy above activation energy
Heterogeneous catalysis (3)	Usually solids. Reactants are gaseous or in solution. The reaction occurs at the surface of the catalyst.
Homogeneous catalysis	Same state Forms intermediate
Methods of measuring rate	Change in volume of gas Measurement of change of mass Colorimetry
Change in volume of gas	This works if there is a change in the number of moles of gas in the reaction.
Calculating IR	Tangent at t=0 Y/X cm3s-1
Labelling axis of Boltzmann curve	Fraction of molecules with energy Collision energy
Effect of Increasing Temperature	Increasing surface area will cause collisions to occur more frequently between the reactant particles This increases the rate of the reaction.

Resource summary

	Created by I Shouldn't be awake over 6 years ago