Energetics

Question 1

What is potential and kinetic energy:?

Answer 1

Is the energy due to the position of the particles

Is the energy associated with the movement of particles

Question 2

What is the heat content/enthalpy?

Answer 2

Is the total amount of energy in chemicals

Question 3

What is the enthalpy change?

Answer 3

is the heat energy measured at constant pressure with the symbol of kJ mol-1

Question 4

What is the system and surroundings?

Answer 4

System- is the chemical products and reactants
Surroundings- is the parts that do not take part in the reaction, anything dipping into the reaction mixture eg thermometer

Question 5

What is the definition of an endothermic and exothermic reaction?

Answer 5

Is the energy absorbed from the surroundings, surroundings decrease in temperature

Is the energy released to the surroundings, surroundings increase in temperature

Question 6

What are 2 differences between endothermic and exothermic reactions?

Answer 6

Breaking the bond between 2 atoms require energy, making the bond between 2 atoms releases energy

If the energy absorbed for bond breaking is greater than the energy released in making new bonds, if the energy absorbed for bond breaking is less than the energy released in making new bonds

Question 7

What is bond energy/bond dissociation energy?

Answer 7

Is the total amount of energy needed to break one mole of a particular bond in one mole of gaseous molecules. Symbol is E

Question 8

What is the standard enthalpy change of reaction, combustion, neutralisation and solution?

Answer 8

is the enthalpy change when the amount of reactants shown in the solution react to give products

is when 1 mole of a substance is burnt in excess oxygen

relates to the enthalpy change for the reaction

when 1 mole of a substance dissolve to from a dilute solution in water

Question 9

What is the standard enthalpy change of formation?

Answer 9

refers to the formation of 1 mole of a compound from its element under standard conditions

Question 10

State Hess’s law

Answer 10

states the total amount of enthalpy change for a chemical reaction is independent of the route by which the reaction proceeds

Question 11

What is the standard enthalpy change of hydration

Answer 11

is when 1 mole of gaseous ions dissolves in water to form a dilute solution

Question 12

What is lattice energy?

Answer 12

is when 1 mole of an ionic compound is formed from its gaseous ions

Question 13

What is the enthalpy change of atomisation?

Answer 13

is the enthalpy change when 1 mole of gaseous atoms informed from the element

Question 14

What is the definition of electron affinity?

Answer 14

is the enthalpy change when 1 mole of electrons is added to 1 mole of gaseous atoms

Question 15

What’s the born haber cycle?

Answer 15

is an enthalpy cycle which includes the enthalpy changes

Question 16

What affects the value of lattice energy?

Answer 16

the size of the ions
the charge of the ions
the way the ions are arranged in the ionic lattice