Energetics I

Question 1

What is the Standard enthalpy change of reaction

Answer 1

this the enthalpy change when the reaction occurs in the molar quantities shown in the chemical equation, under standard conditions

Question 2

Standard enthalpy change of formation

Answer 2

this the enthalpy change when 1 mole of a compound is formed from its elements in their standard states, under standard conditions

2C(s) + 3H2(g) + ½O2(g) → C2H5OH(l)

Question 3

Standard enthalpy change of combustion

Answer 3

this the enthalpy change when 1 mole of a substance is completely burned in oxygen, under standard conditions.

Question 4

Standard enthalpy change of neutralisation

Answer 4

this the enthalpy change when an acid and an alkali react together, under standard conditions, to form 1 mole of water.

Question 5

What are the standard conditions

Answer 5

• 298 Kelvin (25Celcius)
• 100Kpa or 1 ATM

Question 6

State hess law

Answer 6

The total enthalpy change of a reaction is always the same , no matter the route taken