energy (thermal energy) Flashcards
what is thermochemistry?
its a science which is concerned with the heat changes that accompany the chemical changes as well as physical changes
what is the law of conservation of energy?
its a law which states that energy in any physical or chemical change can be neither created or destroyed but it’s transformed from one form to the other
what is thermodynamics ?
a science that deals with the study of energy and how it’s transferred
the combination of hydrogen and oxygen gases to form water is a
( chemical - physical ) change ?
chemical
dissolving ammonium nitrate salt in water represents ( chemical - physical ) change ?
physical
what is the system ?
it is the part of the universe chosen for study , in which physical or chemical change occurs
what is the surrounding ?
it is the part outside the system that exchanges energy or matter or both with the system
what does the system express ?
the reactants and products
what does the system boundary express ?
the wall of the reaction container
what does the surrounding express ?
the medium surrounding the reaction container
describe the open system ( what exchanges )
energy and matter can be exchanged
describe closed system ( what can be exchanged )
only energy can be exchanged
describe isolated system ( what can be exchanged )
nothing is exchanged
why is the medical thermometer a closed system?
as it allows the exchange of energy only with the surrounding in the form of heat
