5 energetics Flashcards
define heat
transfer of energy between objects of different temperature
what is thermal equilibium
when two objects reach the same temperature and so no more energy is transferred
what is enthalpy
heat content of the system
ΔHƟ meaning
enthalpy change under standard conditions
what are standard conditions
pressure of 100,000 Pa
temperature of 298K
define temperature
average kinetic energy of the particles in a substance
what is absolute temperature proportional to
average kinetic energy of particles in a sample
what is absolute temp
0K, where the particles have the least amount ofkinetic energy
what is an open system
where matter and energy can move freely between the system and surroundings
what is a closed system
where enrgy or matter is not exchanged with the surroundings
what do thermochemical equations show
enthalpy change of reaction
q =
mc∆T
what is q
heat absorbed or released in J
what is c
the specific heat capacity of the solution in J g−1 °C−1 or J g−1 K−1
what is m
is the mass of solution in g
what is ∆T
is the change in temperature in oC or K
specific heat capacity def
the amount of heat required to raise the temperature of one gram of a substance by one degree Celsius or one kelvin. The units of specific heat capacity are either joules per gram per degree Celsius (J g−1 °C−1) or joules per gram per kelvin (J g−1 K−1).
what does ΔHn mean
enthalpy change of neutralisation
what is enthalpy change of neutralisation
the enthalpy change when an acid and base react together to form one mole of water.
how can enthalpy changes be calcualted
from their effect on the temperature of their surroundings
what is heat
form of energy
what is temperature
a measure of the average kinetic energy of the partiles
when is enthalpy change negative
exothermic reaction
when is enthalpy change positive
endothermic reaction