enthalpy changes

Question 1

enthalpy change of reaction

Answer 1

enthalpy change when the number of moles od reactions as specified in balanced equation react together

Question 2

standard enthalpy of formation

Answer 2

enthalpy change when 1 mole of a compound is formed from its elements under standard conditions and all reactants in standard states

Question 3

enthalpy change of combustion

Answer 3

enthalpy change when one mole of a substance
combusted completely in oxygen under standard conditions and all reactants and products in their standard states

Question 4

enthalpy change of neutralisation

Answer 4

enthalpy change when solutions of an acid and alkali react together under standard conditions to produce 1 mole of water

Question 5

error in calorimetric method

Answer 5

energy transfer to surrounding
slow reaction or incomplete
approximating specifc heat capacity of water

Question 6

error in enthalpy of combustion

Answer 6

incomplete combustion of fuel
evaporates of fuel after weighing
not done sunder standard conditions as h20 gas not liquid in experiment

Question 7

mean both enthalpy

Answer 7

enthalpy change when one mole of bonds of gaseous covalent bonds is broken always positive as energy needed to break bond

Question 8

exothermic reaction in terms of bonds

Answer 8

more energy released making bonds than absorbed breaking bonds

Question 9

endothermic reaction in terms of bonds

Answer 9

more energy absorbed breaking bonds than released when making bonds

Question 10

enthalpy chang hof formation equation

Answer 10

RPR

Question 11

enthalpy change of combustion formula

Answer 11

RRP