Unit 1 Flashcards
Activation energy definition
The minimum kinetic energy required by colliding particles before reaction will occur, since a high energy activated complex must be formed
2 requirements for a reaction to occur?
- particles must collide with sufficient energy (equal or greater than activation energy)
- particles must be in the correct orientation
Activated complex
the activated complex is a very unstable arrangement of atoms formed at the maximum of the potential energy barrier, during a chemical reaction
when does adsorption occur?
occurs when molecules become bonded to the surface of a catalyst
definition of enthalpy change for a reaction?
the change in heat energy when 1 mole of reactant is converted to product(s) at constant pressure.
what can cause an enzyme to become denatured?
high temperatures or extremes of pH
what does the total area under the kinetic energy graph represent?
the total number of particles in the system
what does the shaded area in a kinetic energy graph represent?
particles which have a kinetic energy higher than the activation energy so can react and form products
what does the unshaded area in a kinetic energy graph represent?
particles that have too little energy to react
what must be put in to start a chemical reaction?
energy
what is given out from a chemical reaction when new bonds are formed?
energy
exothermic reactions release energy to the surroundings so the amount of stored energy decreases so deltaH…
is always negative
endothermic reactions take in energy from the surroundings so the amount of stored energy increases so delta H…
is always positive
