Standard Enthalpy Change of Combustion:

Question 1

Standard Enthalpy Change of Combustion?

Answer 1

= = enthalpy change when 1 mole of a solution reacts completly with oxygen under standard conditions in standard states

Question 2

How do we determine the standard enthalpy change of combustion of a liquid for example ethanol?

Answer 2

= combust fuel, use the thermal energy released to heat a known mass of water
= measuring temperature change of water can determine the standard enthalpy change of combystion

Question 3

What are the equipment of this?

Answer 3

= spirit burner- ethanol
= metal can with fixed mass of water- calorimeter
= thermometer- measures temperature
=

Question 4

What is the method?

Answer 4

1) use balance to measure starting mass of spirit burner of the fuel + use therometer to measure the start temperature of water
2) remove cap from spirit burner and immediatley light the wick- do not leave uncapped if unlit (fuel will evaporate)

thermal energy released causes temperature of water to increase
3) stir water with the therometer so it is distributed, after several minutes we extinguish the flame by replacing the cap + measure temp of water
4) use balance to measure the final mass of the spirit burner and the fuel
substrat from final by start to determine what conbusted