Chapter 4 Defintions Flashcards
absolute temperature scale
a temperature scale that only has positive values since 0 K is defined at the point where there is no thermal motion for any known species. There is a linear relationship between this scale and the celsius scale: temperature (degrees celsius) = temperature (K) -273
biofuel
energy source produced from renewable sources such as crops.
combustion
a reaction with oxygen to form the oxides of each of the elements present; with adequate oxygen, combustion of a hydrocarbon will produce carbon dioxide and water.
endothermic
A chemical or physical change where the chemical energy of the product is greater than the chemical energy of the reactant; hence, heat energy is absorbed.
enthalpy
the total energy possessed by a chemical substance at a constant pressure; it is usually expressed as a change in enthalpy
exothermic
a chemical reaction or physical change where the chemical energy of the product is less than the chemical energy of the reactants; hence, heat energy is released
fossil fuel
an energy source, such as crude oil and coal, produced from the decayed remains of animals and plants
heat of combusion
heat released when a fuel undergoes complete combustion at a standard atmospheric pressure
ionic equation
equation that gives information about all species in the reaction; aqueous solutions are written as separate ions; for example NaCl (aq) is written as Na+ and Cl-
net ionic equation
an equation that only contains the ions that take part in a chemical reaction; spectators are excluded
species
a general term that refers to atoms, ions and molecules
spectator ion
an ion that is present in the same form on each side of the equation
specific heat capacity
heat energy required to raise the temperature of 1 gram of substance by 1 kelvin
