thermochemistry - chem 30 Flashcards
1
Q
Kinetic Energy
A
- Energy in motion, motion of particles, molecules or atoms
2
Q
Potential Energy
A
- Stored energy, energy stored within chemical bonds
3
Q
Exothermic Reactions
A
- Release energy to surroundings
- Reactants have more potential energy stored than the products. The excess energy is released to the surroundings, increasing kinetic energy therefore increasing the temperature
4
Q
Endothermic Reactions
A
- Absorb energy from surroundings
- Reactants have less potential energy than the products. The needed energy is absorbed to the surroundings, decreasing the kinetic energy, therefore decreasing the temperature
5
Q
Calorimetry
A
-Method of measuring energy changes in an isolated system
6
Q
-Calorimeter
A
- instrument used to measure the amount of energy absorbed or released in a chemical reaction or phase change
7
Q
Assumptions made with Calorimetry
A
- The system is isolated, no energy is leaving
- The heat that is exchanged with the styrofoam cup, or any other instrument is negligible
- If something dissolves or reacts with water, the properties in the resulting solution do not change
- The process takes place under constant pressure
8
Q
Molar Enthalpy
A
- enthalpy change in a chemical system for 1 mol of the specified chemical that is undergoing the reaction. Can be calculated for both reactants and products
9
Q
Collision Theory of Reactions
A
- Particles must collide in order for chemical reactions to occur. For reactions to be effective, they must be in the correct orientation and have enough energy
10
Q
Difference between open, closed and isolated systems
A
- open: both matter and energy can move
- closed system: only energy can move
- isolated system: neither energy nor matter can move
11
Q
The change in enthalpy is equal to …..
A
…. the heat gained or lost by a system
