Chapter 7- Flashcards
(22 cards)
Change in enthalpy
Delta H: it is the energy difference between the products and the reactants of a chemical rxn
Delta H < 0 exothermic
Delta H > 0 endothermic
Enthalpy
A function representing heat under conditions of constant pressure
Which is spontaneous, exo or endo?
Exothermic
Entropy
The measure of the statistical distribution of energy in a system
Gases>liquid>solid
Gibbs free energy (G)
A function which considers both the entropy and enthalpy of a system
Thermodynamics
The study of energy, work, and heat
System
Contains the process under study
Surroundings
The universe
Energy can be gained or lost by the system from the surroundings
1st law of thermodynamics
Energy cannot be created or destroyed
2nd Law of Thermodynamics
The universe spontaneously tends toward increasing entropy
3rd Law of Thermodynamics
The entropy of a pure crystal at absolute zero is 0
Exothermic Rxn
Releases energy to it’s surroundings
Endothermic Rxn
Absorbs energy from it’s surroundings
Ions with the same charge
Repel
Rate generally increases as the what increases?
Concentration and temperature
Calorimetry
The measurement of heat energy changes in a chemical Rxn
Specific Heat (Cs)
The amount if heat (calories or joules) needed to raise the temperature of 1 gram of the substance 1 degree Celsius
How do you find the amount of heat that is absorbed or released?
Q = Ms x deltaT x Cs
Ms is grams
Delta T is temp
Cs is specific heat
Fuel value
The amount of energy per gram of food
1 Cal =
1 kilocalorie or 1000 Cal
Chemical Kinetics
The study of rate of chemical rxns
Mechanism
A step by step description of how reactants become products
