How do we measure the energy content of substances?
in calories
A calorie is the quantity of heat needed to raise the temperature of 1 gram of pure water 1oc.
Dietary calorie=energy in food.
Usually measured in kilocalories=1C=1000 calories.
Thermal Energy
will always flow from a warm object to a cool object until both objects are the same temperature.
Symbol Q?
represents thermal energy or heat.
Heat
is a from of energy
1st Law of Thermodynamics
=conservation of energy. states that in any chemical rxn or physical process, energy can be converted from one from to another, but it is neither created nor destroyed.
potential energy is stored in a substance because?
of its composition, type of atoms in the substance, number and type of bonds joining the atoms, and the way that the atoms are arranged.
Kinetic Energy
Is directly related to the constant motion of its atoms or particles and is proportional to the substance's temperature.
Energy
is the ability to do work or produce motion
What is thermochemistry?
the study of changes in heat that accompany chemical reations and phase changes.
Universe
is the system and the surroundings
Surroundings
Are everything in the universe other than the system.
What is a system?
A system is the specific part of the universe that contains the reaction or process you wish to study.