Energetics Flashcards
What is an exothermic reaction?
Reaction that releases heat and causes rising temperature energy transferred from system to surroundings internal energy of the system decreases as it’s lost to surroundings and products are more stable as they are lower than energy than reactants
What is an endothermic reaction?
Reaction that takes in heat energy transferred from surroundings to system taken heat from surroundings so there’s a fall in the outside temperature and then the internal energy of the system increases and the reactants are more stable than the products as they are lowering energy
What is the enthalpy?
The total energy content of a system heat control of the system. The higher the energy content of a system the unstable is.
Define enthalpy change
The heat energy change at constant pressure
What are standard conditions?
Pressure equals 100 kPa
Temperature equals 298 K (25°)
Concentration equals 1.0 (for reactions with aqueous solutions)
What is the standard state?
Physical state of a substance under standard condition
What elements are the only liquid standard state?
Mercury and bromine
Define enthalpy of combustion
Be changed when one mole of a substance is completely burned in oxygen under standard conditions or reactants and products are in the standard state
Define enthaly of formation
The enthalpy change when one mole of a compound is formed from its constituent elements understanding conditions and all reactants and products are in the standard state
What is heat and temp measured in?
Heat(joules)
Temperature (kelvin/celsius)
What does the amount of energy in a system depend on?
Temperature
Mass
Material
Define calorimeter
Determining heat absorbed evolved or transferred
What is the heat energy required to change the temp of a substance ?
Q=mc(change in T)
