Uncertainty in Thermometer = 0.5oC
Volume of Acid Taken = 10 ml
Volume of Base Taken = 10 ml
Least count in Measuring cylinder = 1ml
Uncertainty in measuring cylinder = ± 0.5ml
Molarity of Acid = 1M
Molarity of Base = 1M
Processed Data
To find enthalpy we can use this equation:
Where E = Energy transfer between system and surroundings
m = Mass of Substance
c = Specific Heat capacity of substance
∆T = Change in Temperature
Volume of solutions cup (Salt + Water) after reaction = 10ml (± 0.5ml) + 10ml (±0.5ml) = 20ml (± 1ml)
Density of water is 1 g/ml. Therefore mass of Salt + Water after reaction = 20 g (± 1 g)
Change in temperature = Peak Temperature – Temperature before adding base
= 27.2oC (± 0.5 oC) - 22.3 oC (± 0.5 oC)
= 4.9 oC (± 1 oC) OR 4.9K (± 1K)
Percentage error in mass of water:
Percentage error in temperature:
Percentage error in number of moles =
Energy released in reaction:
Moles of Hydrogen ions neutralized by Hydroxide ions =
=
= 0.01 moles (±0.0005 moles)
Energy released per mole of hydrogen ions neutralized =
=
= 40960 J mol-1 or 40.96 kJ mol-1
41.0 kJ mol-1
Total uncertainty for enthalpy value = 20.4% + 5% + 5% = 30.4%
Absolute uncertainty=
The standard enthalpy change of neutralization of a weak acid (CH3CO2H) by a weak base (NH4OH)
= -41.0 kJ mol-1 ± 12.5 kJ/mol-1
The percentage error compared to literature value:
