Chapter 6 Flashcards
whats difference between thermodynamics and thermochemistry
thermodynamics studies the relationship between heat and energy
thermochemistry is study of heat in chemical reactions
what’s the nature of energy
energy is the ability to do work or produce heat
state the law of conservation of energy
enrgy cant be created or destroyed, it can only be transformed from one form to the other
state the most relevant forms of energy
-kinetic due to motion
potential due to position
-temperature due to motion of particles
-heat due to transfer of energy between substance because of a temp difference
-work : force acting over a distance
true or false
variation of Energy is a state function
true
true or false
work and heat are state functions
false
what are the two types of reaction in thermochemistry
exo: heat is released=energy taken out of system=vessel heat up and q has negative value
endo: heat is absorbed=energy added to the system=vessel cools down and q is positive
define enthalpy
change in temperature when pressure is constant
Is enthalpy a state function
yes
what do a variation of enthalpy mean
heat absorbed or released by chemical reaction under constant pressure
what is calorimetry
study of measuring heat
define specific heat capacity and molar heat capacity
S= energy neeeded to raise 1 g of substance by 1 degree celcius
M= energy neeeded to raise 1 mol of substance by 1 degree celcius
whats the formula for heat
q=m x s x delta t
define Hess’s law
change in enthaply can be obtain through one or multiple steps
when considiring enthalpy of reaction, the sign must be reversed if reaction is reversed
if coefficient mutliplied by integer enthalpy is multiplied by same integer
true or false
the energy of covalent bonds can be used to find the enthalpy of a rxn
true
