Enthalpy changes

Question 1

What are the standard conditions

Answer 1

pressure =1atm
Temperature =25c or 298K

Question 2

What is the standard enthalpy change of neutralisation

Answer 2

the enthalpy change that occurs when solutions of an acid and an alkali react together to form 1 mole of water under standard conditions

Question 3

What is the enthalpy change of formation

Answer 3

The enthalpy change that occurs when 1 mole of a compound is formed from its constituent elements in standard states

Question 4

what is the enthalpy change of combustion

Answer 4

the enthalpy change that occurs when 1 mole of a substance reacts completely with oxygen under standard conditions

Question 5

what is the enthalpy change of reaction

Answer 5

enthalpy change that occurs when a reaction occurs in the molar quantities shown in the chemical equation under standard conditions

Question 6

what is the overall enthalpy change for an exothermic reaction

Answer 6

negative
products end up with less energy than the reactants

Question 7

what is the overall enthalpy change of an endothermic reaction

Answer 7

positive
products end up with more energy than the reactants

Question 8

what is the activation energy

Answer 8

the minimum energy needed to begin a reaction by breaking reactant bonds

Question 9

what is the overall enthalpy of breaking bonds

Answer 9

endothermic , so positive

Question 10

what is the overall enthalpy of making bonds

Answer 10

exothermic delta h negative

Question 11

how do you calculate the total enthalpy change of reaction

Answer 11

total energy absorbed - total energy released