Energy from Fuels Flashcards
Heat
The thermal energy of an object
Temperature
A measure of hotness
Specific heat capacity
The energy required to raise the temperature of 1g of a substance by 1˚C
∆H = …
∆H = total energy needed to break bonds - total energy released when bonds form
Bond energy
The amount of energy required to break one mole of a type of chemical bond. Breaking bonds requires energy; making bonds releases energy
Exothermic
Energy is given out to the surroundings in the reaction; ∆H is negative
Endothermic
Energy is taken in from the surroundings in the reaction; ∆H is positive
∆Hcᶿ
Standard molar enthalpy change of combustion: the enthalpy change when one mole of a substance in its standard state at a specified temperature and pressure (298K, 25˚C; 1 atmosphere) is completely combusted in air
∆Hfᶿ
Standard molar enthalpy change of formation: the enthalpy change when one mole of a substance is formed from its elements in their standard states at a specified temperature and pressure (298K or 25˚C; 1 atmosphere)
Hess’s Law
The enthalpy change for a reaction is independent of the route taken. Routes begin when arrows diverge and end when they converge again
Homologous series
A group of molecules with similar chemical or physical properties
Carbon
The first group 4 element of the periodic table, Carbon forms strong covalent bonds with itself to form rings and chains (catenation).
Isomers
Elements with the same molecular formula but different arrangements of atoms
Allotropes
Different forms of the same elements
Alkanes
Saturated, non polar hydrocarbons with general formula CnH2n+2. Physical properties, such as melting point and density, change as the number of carbon atoms increases
