How do we measure enthalpy change?

Question 1

What are the three methods of measuring enthalpy change?

Answer 1

• Hess Law
• Bond enthalpies
• Using experimental methods, calorimetry

Question 2

What is the equation for calorimetry?

Answer 2

Q = Mass x specific heat capacity x change in temperature
Change in enthalpy = Q / moles

Question 3

What affects the accuracy of the change in combustion by calorimetry

Answer 3

• Heat loss to the surroundings other than water
• Incomplete combustion of a fuel which produces carbon monoxide and soot
• Evaporation of the fuel from the wick, affecting the mass of the spirit burner after extinguishing
• Non-standard conditions