Standard enthalpy changes

Question 1

To be able to compare the changes in enthalpy between reactions, all thermodynamic measurements are carried out under

Answer 1

standard conditions

Question 2

To be able to compare the changes in enthalpy between reactions, all thermodynamic measurements are carried out under standard conditions

These standard conditions are

Answer 2

A pressure of 100 kPa (you may see some older exam questions that use a figure of 101 kPa;

A temperature of 298 K (25 oC)

Each substance involved in the reaction is in its standard physical state (solid, liquid or gas)

Question 3

To show that a reaction has been carried out under standard conditions, the symbol ……….is used

Answer 3

Ꝋ

Question 4

ΔHꝊ =

Answer 4

the standard enthalpy change