Chemistry Thermochemistry.

the study of the energy changes that accompany physical and chemical changes in matter

the energy released by the surroundings in a chemical reaction as a result of the motion of the molecules

a set of reactants and products being studyied in a chemical equation

All matter around the system responsible for absorbing or releasing thermal energy - usually water

heat (q) is transferred between the system and the surroundings

exothermic: the system releases energy to the surroundings (- delta h, but positive q) - reactants at higher energy than products - usually feel cold

Endothermic: The system absorbs energy from the surroundings (+delta h, but - q) - products at higher energy than reactans - usually feels hot

its temperature increases as well

Open system: a chemical reaction that produces gas - energy and matter can flow in and out of the system.

isolated system: neither matter nor energy can move in or out of the system

closed system: energy can move in or out of the system, but not matter - calorimeter.

using q=mct
where m is the mass in g, t is the change in temperature (final-initial) and c is the specific heat capacity of the surroundings (usually water)

4.18 j/mol*ºC

Jules

divide by 1000

mass = volume * density in aqueous solutions

the difference in enthalpy between reactants and products during a reaction. (delta H)

when q is positive, delta H is negative

the enthalpy change associated with a physical, chemical or nuclear change involving one mole of a substance (delta Hx)

delta Hx = delta H/moles