Chemical Energetics Flashcards
exo - like exit
What energy change occurs in an exothermic reaction?
An exothermic reaction transfers thermal energy to the surroundings leading to an increase in the temperature of the surroundings
For example, a fire.
endo - sounds like into i.e coming into
What energy change occurs in an endothermic reation?
An endothermic reaction takes in thermal energy from the surroundings leading to a decrease in the temperature of the surroundings.
What is the transfer of energy in a reaction called?
Transfer - in or out
The transfer of energy in a reaction is called an enthalphy change, ∆H.
Define Activation Energy, Ea.
Activation Energy, Ea, is the minimum amount of energy that colliding particles must have to react.
What is bond breaking, an Endothermic or Exothermic process?
A reaction needs energy to occur, inorder to break bonds.
Bond breaking is an Endothermic process.
What is bond making, an Endothermic or Exothermic process?
Bond making is an exothermic process.
What is a positive enthalpy change?
Endothermic or Exothermic
A positive enthalpy change is endothermic
∆H = positive
What is a negative enthalpy change?
Endothermic or Exothermic
A negative enthalpy change is exothermic.
∆H = Negative
What is bond energy?
Bond energy is the energy required to break a bond.
Measured in kJ/mol
What formula is used for the calculation of enthalpy change?
∆H = bond breaking energy - bond formation energy
In a reaction pathway diagram, the distance between the reactants and the products is the what?
In a reaction pathway diagram, the distance between the reactants and the products is the enthalpy change, ∆H.
In a reaction pathway diagram, the distance between the peak energy point and the reactants is the what?
In a reaction pathway diagram, the distance between the peak energy point and the reactants is the Activation Energy, Ea.
What is enthalpy change, ∆H, measured in?
Enthalpy change, ∆H, is measured in kilojoules per mole.
In an endothermic reaction, which has more energy, the reactants or the products?
In a reaction pathway diagram specifically | more energy = higher up
In an endothermic reaction, the products have more energy than the reactants.
Thus they (products) are higher up on the reaction pathway diagram.
In an exothermic reaction, which has more energy, the reactants or the products?
In a reaction pathway diagram specifically | more energy = higher up
In an exothermic reaction, the reactants have more energy than the products.
Thus they (reactants) are higher up on the reaction pathway diagram.
