Chem Practice Unit 9

Vocab

• Energy: The ability to do work or produce heat

• Kinetic Energy: Motion energy

• Potential Energy: Stored energy, energy capable of becoming kinetic energy

• Law of Conservation of Energy/First Law of Thermodynamics: In ANY chemical/physical process, energy can be converted from one form to another, but energy is neither created nor destroyed. (Movement of heat energy)

• Heat takes the form of energy transferring from high→low

• Calorie: Heat required to raise the temperature of 1g of water 1 degrees celsius

• Joule: SI Unit for energy. 1 cal=4.184 J

• Specific heat: Heat required to raise the temperature of 1g of any substance 1 degrees celsius

• Calorimeter: Well insulated cylinder with a thermometer and a liquid-like water is inside. It is used to determine the specific heat of an unknown substance.

• Enthalpy: The energy contained in a system at constant pressure. We can measure the change in this when the reaction takes place.

• Standard conditions for thermodynamic changes: 1 atm pressure, 25 degrees celsius, or 298 K

• Exothermic: Energy is RELEASED (graph: up to down) 

• Endothermic: Energy is ABSORBED (graph: down to up)

• Spontaneous process: Occurs without outside intervention. The energy required for the reaction is already present 

• Entropy (S): A measure of the numbr of possible ways the energy of a system can be distributed/arranged. 

• Second Law of Thermodynamics: The entropy of the universe is always increasing, (total energy in the universe→energy is always going up)

• Aqueous: Surrounded by water

• Synthesis reactions usually: Decrease in entropy