| concept |
definition |
| First Law of Thermodynamics |
conservation of energy and mass, energy is neither created nor destroyed |
| heat |
energy that flows from hotter to colder object |
| temperature |
property that determines the direction of heat flow |
| combustion |
combination of fuel and oxygen to form products |
| exothermic reaction |
term applied to any chemical or physical change accopanied by the the release of heat. |
| Calorimeter |
measures quantity of heat energy releaswed in a combustion reaction. ex: burning coal |
| Endothermic reaction |
any chemical or physical change that absorbs energy. ex: melting ice |
| activation energy |
energy necessary to initiate a reaction |
| Tetraethyl lead substitues |
1) Ethanol 2) MTBE |
| Entropy |
randomness in position or energy level (going from order to disorder) Increase in entropy: exothermic. Decrease in entropy: endothermic |
| second law of thermodynamics |
energy is lost through heat |
| Oil - refining process |
crude oil (petroleum) refining process: crude oil separeted into fractions that consist of compounds with similar properties. |
| Distillation |
a purification, or separation, process in which a solution is heated to its boiling point and the vapors are condensed and collected. |
| isomers |
compounds with the same chemical formula but different chemical structure. ex. octane and isooctane |
| Cracking |
chemical process by which large moclecules are broken into smaller ones suitable to be used in gasoline |
| thermal cracking |
achieved by heating the starting materials to a high temperature |
| catalytic cracking |
catalysts are used to promote molecular breakdown at lower temperatures |
| oxygenated gasolines |
blends of petroleum-derived hydrocarbons with oxygen-containing compounds such as MTBE, ethanol or methanol |
| Reformulated Gasolines |
oxygenated gasolines that also contain a lower percentage of certain more volatile hydrocarbons such a benzene found in nonoxygenated conventional gasoline |
| biomass |
materials produced by biological processes |
| refinery gases |
Most volatile components of the fractionating tower boil far below room temperature |
| hydrocarbons |
molecules consisting of only hydrogen and carbon atoms |
| Alkanes |
hydrocarbons with only single bonds between carbons |
| bond energy |
the amount of energy that must be absorbed to break a specific chemical bond |
| heat of combustion |
quantity ofr heat energy given off when a specified amount of a substance burns in oxygen |
| thermal energy |
random motion of molecules |
| potential and kinetic energy |
potential: form of energy related to positions of atoms and molecular structure and stored in chemical bonds. kinetic: energy in motion |
| calorie |
amount of heat necessary to raise the temperature of exactly one gram of water by one degree Celsius. 4.184 J |
| work |
done when movement occurs against a restraining force. Work is equal to force multiplied by distance over which motion occurs |
Science Vocab 147928
