thermodynamics

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Total cards: 24•Content version: v4•Public deck•Updated: 8/1/2026

Card preview (24)

Front (Question)

in exothermic reactions are bond broken or made

Back (Answer)

in exothermic reactions bonds are formed

Front (Question)

in endothermic reactions are bonds broken or made

Back (Answer)

in endothermic reactions bond are broken

Front (Question)

what factor does the size of an enthalpy change depend on

Back (Answer)

• the strength/energy of a bond or force (stronger bonds /forces produce a larger enthalpy change

Front (Question)

define enthalpy change of formation

Back (Answer)

the enthalpy change when 1 mole of substance is formed from it’s constituent elements in their standard states under standard conditions and pressure

Front (Question)

write an equation for the enthalpy change of formation for NaCl

Back (Answer)

Na (s) + 1/2 Cl2 —-> NaCl (s)

Front (Question)

define enthalpy change of lattice formation

Back (Answer)

the enthalpy change when one mole of an ionic compound is from from it’s component ions in a gaseous state

Front (Question)

write an equation for the enthalpy change of lattice formation of NaCl

Back (Answer)

Na+ + Cl- —-> NaCl (s)

Front (Question)

what type of energy change is enthalpy change of lattice formation and why?

Back (Answer)

exothermic it is forming an electrostatic attraction (ionic bond)

Front (Question)

what are the 2 factors that affect enthalpy change of lattice formation and explain why they affect it?

Back (Answer)

charge on ion = higher charge = strong electrostatic forces between ions = more exothermic lattice formation enthalpy size of ion = smaller ionic radius = stronger electrostatic forces between ions = more exothermic lattice formation enthalpy

#10

Front (Question)

define enthalpy change of atomisation

Back (Answer)

the enthalpy change when one mole of gaseous atoms are formed

#11

Front (Question)

write the equation for the enthalpy change of atomisation of Na

Back (Answer)

Na (s) —> Na (g)

#12

Front (Question)

write an equation for the enthalpy change of atomisation of Cl

Back (Answer)

1/2 Cl2 (g) —-> Cl (g)

#13

Front (Question)

write an equation for the enthalpy change of atomisation of Br

Back (Answer)

1/2 Br2 (l) —-> Br (g)

#14

Front (Question)

write an equation for the enthalpy change of atomisation of S

Back (Answer)

1/8 S8 (s) —-> S (g)

#15

Front (Question)

what type of energy change is enthalpy change of atomisation and why

Back (Answer)

endothermic, as breaking bonds of attraction

#16

Front (Question)

define 1st ionisation enthalpy

Back (Answer)

The enthalpy change to remove 1 mole of electrons from 1 mole of gaseous atoms to form 1 mole of gaseous 1+ ions

#17

Front (Question)

write an equation for the 1st ionisation enthalpy for Na

Back (Answer)

Na (g) —-> Na+ (g) + e-

#18

Front (Question)

what type of energy change is the 1st ionisation enthalpy change

Back (Answer)

Endothermic, overcoming electrostatic attraction between nucleus and outer electron

#19

Front (Question)

what factors affect the 1st ionisation energy

Back (Answer)

• nuclear charge • electron shielding • size of ion

#20

Front (Question)

define bond dissociation enthalpy

Back (Answer)

the enthalpy change when 1 mole of covalent bonds are gaseous state

#21

Front (Question)

write an equation for the bond dissociation enthalpy of Cl

Back (Answer)

Cl2 (g) —-> 2Cl (g)

#22

Front (Question)

define 1st electron affinity

Back (Answer)

the enthalpy change to add 1 mole of electrons to 1 mole of gaseous atoms to make 1 mole of gaseous ions with a -1 charge

#23

Front (Question)

write an equation for the 1st electron affinity of Cl (g)

Back (Answer)

Cl (g) + e- —–> Cl- (g)

#24

Front (Question)

what type of energy change is 1st electron affinity

Back (Answer)

exothermic as an electrostatic attraction between nucleus and electron is being formed