Slides in this set
· Exothermic: negative delta H.
The products are at a lower
energy level. Energy
surroundings (get hotter).
Bonds are made. E.g:
· Endothermic: positive delta
H. Products are at a higher
temperature than reactants.
Energy has been absorbed by
the system. Surroundings get
colder. Bonds break. E.g:
298K and 100Kpa
· H reaction: enthalpy change under standard conditions for
the reaction in the molar quantities written in the chemical
· H formation: enthalpy change when 1 mole of a compound
is formed from its elements under standard conditions.
· H Combustion: enthalpy change when 1 mole of a substance
is completely burnt in excess oxygen under standard
· H Atomization: enthalpy change when 1 mole of atoms in
the gaseous state is formed from the elements under
· H neutralisation: enthalpy change when 1 mole of water is
formed by the reaction of an acid and alkali under standard
· M- mass
· C- specific heat capacity
· T- Change in temperature
Specific heat capacity: amount of energy required to
increase 1cm3 or 1g of a substance by 1 degree.
Therefore, 1cm3 of water must have an input of 4.2
KJ/mol of energy to increase it's temperature.
1cm3= 1g= 1ml due to density of water= 1.…read more
Assumptions on MCT calculations
· All the energy produced is transferred
· No heat is absorbed by equipment
· No heat loss to the room or surface of liquid
· Fuel has combusted completely
· Assumptions= rise in systematic errors.
· All water based solutions have the same heat
capacity as water.…read more