Thermochemistry Flashcards
What does the collision theory say about the energies of atoms, ions, or molecules reacting to form products when they collide
Particles must have enough kinetic energy when they collide for a reaction to happen.
In a typical reaction, as time passes, the amount of _______ decreases and the amount of _______ increases
Reactant, product
What factors affect the rate of reaction of reaction
Volume: more molecules mean the greater the reaction rate
Temperature: the measurement of the reaction energy of molecules
Catalyst: a catalyst changed the activation energy and thus increases the rate if reaction
Surface area: a decrease in surface area means an increase in reaction rates - the smaller the particle size, the larger the surface area of a given mass
Particle size
The minimum amount of energy that particles must have in order to react is called the
Activation energy
Lifetime of an activated complex
10^-13 s
Why is an activated complex sometimes called the transition state?ii
It is unstable and is as likely to re-form reactants as it is to form products
Enthalpy
The heat content of a substance
Hess’s law of heat summation
If two or more thermochemical equations are added to give a final equation, their heat changed can be added to determine the final heat change.
Calorimetry
The accurate and precise measurement of heat flow for chemical and physical processes
the quantity of heat needed to raise the temperature of 1g of pure water 1 degree C.
Calorie
The amount of heat needed to increase the temperature of an object exactly 1 degree C.
Heat capacity
Joule
SI unit for heat and energy
Specific head
The amount of heat required to raise the temperature of 1g of a substance 1 degree C
Endothermic
System is gaining heat
A + q > C + D
Exothermic
The system is losing heat
A + B > C + q
