1. Rates of Reaction Flashcards
What is a “distribution curve”?
Distribution curve example
Collision energy distribution graph
What is “activation energy” ?
The minimum kinetic energy at which colliding particles could form an activated complex
What is…
A. The symbol for activation energy?
B. The unit it is measured in?
A. Ea
B. kJ mol-1 (kilojoules per mol)
Why might not all collision with energy greater than Ea be successful
Particles may collide with incorrect geometry
Explain the effect of increasing concentration on reaction rate using collision energy distribution graph
The area under the curve to the righ of Ea value increases showing more successfull collisions are possible
Explain the effect of increasing concentration on reaction rate using collision energy distribution graph
Explain the effect using a catalyst has on reaction rate
What is an “activated complex” ?
An unstable arrangement of atoms (where old bonds are being broken and new bonds are being made) at the maximum of the potential energy barrier
What is enthalpy?
A measure of the change in potential energy between the reactants and the products of a reaction.
What enthalpy values do exothermic reactions have?
-ve
What enthalpy values do endothermic reactions have?
+ve
What are some examples of endothermic reactions?
- Dissolving certain salts in water, e.g. ammonium nitrate or potassium nitrate.
- Neutralising ethanoic acid or sodium hydrogecarbonate.
What are some examples of exothermic reactions?
- Combustion - hydrocarbons and carbon compounds.
- Neutralisation - Using alkalis and reactive metals
What is the symbol for enthalpy change
