AP Chem - Chapter 6 - Energy Flashcards
what is the law of conservation of energy
energy cannot be created nor destroyed
what is energy
for our purposes, the capacity to produce heat
what is heat
the transfer of energy
what is temperature
a measure of kinetic energy
what is the relationship between temperature and kinetic energy
directly proportional
what is a state function
refers to a property of the system that depends only on its present state. a change in this function in going from one state to another state is independent of the particular pathway taken between the two states
is energy a state function
yes
is wrok a state function
no
is heat a state function
no
what is endothermic
refers to a reaction where energy (as heat) flows into the system
what is exothermic
refers to a reaction where energy (as heat) flows out of the system
if a reaction has a negative change in H, it is
exothermic
if a reaction has a positive change in H, it is
endothermic
energy released is
exothermic
energy absorbed is
endothermic
what is a calorimeter
a device used experimentally to determine the heat associated with a reaction
what does q stand for
heat
what is specific heat capacity
the amount of energy needed to raise the temp of 1 g of a substance by 1 degree C
what are the units for specific heat capacity
J/degree C x g
is the heat of reaction/change in enthalpy intensive or extensive
extensive
is temperature intensive or extensive
intensive
is change in enthalpy a state function
yes
what is Hess’s law
in going from a particular set of reactants to a particular set of products, the change in enthalpy is the same whether the reaction takes place in one step or a series of steps
what happens to the change of H if a reaction is reversed
the sign of change of H is reversed
what do you do to the value of the change of H if the coefficients in a balanced equation are multiplied by an integer
multiply the change of H by the same integer
what is standard enthalpy of formation
the change in enthalpy that accompanies the formation of one mole of a compound from its elements with all substances in their standard states
what are “standard state” temperature and pressure
25 degrees celcius
1 atm
what is the standard state concentration for a substance in a solution
1 M
how do you find the change in enthalpy for a given reaction using standard enthalpies of formation
using the chart, add the standard enthalpies of formation pf the reactants and of the products (elements are not included; they’re 0). Then multiply each SEF by the amount of moles you have of it. Then subtract what you get for the products from what you got for the reactants.
