Equations

Question 1

How do we calculate thermal change in energy?

Answer 1

q: m x c x delta T
q: energu change of water (Joules)
m: mass of water (g)
c: specific heat capacity J g -1 k -1
deltaT: temperature change of water (celcius)

Question 2

How do we useQ to determine the standard enthalpy change of combustion? Kj m -1

Answer 2

= per mole is the amount of fuel used
= -q/moles

Question 3

Why may the actual answer be higher than the answer you have gotten?

Answer 3

= if you leave the spirit burner uncapped, the fuel evaporates - burnt more fuel than actually needed
= less exothermic than actually was
= a lot of heat energy released by the fuel does not pass into the water
= transfered to metal calomriter + air

=not all fuel is cp bisted= ibcomplete less thermal energy
= not standard conditions