Step 6: Repeat steps 1-5 8 more times for a total of 9 trails changing the mass of Mg in step 4 every 3 trails from 0.02g ± 0.001g to 0.03g ± 0.001g to 0.04g ± 0.001g.
Data
Calculations:
When a sample of Mg dissolves in 10mL HCl, the temp increases. The following are the ΔH of the 9 trials:
Equation: q=mcΔT
Trial 1 0.02g ± .001g Mg
- (10mL)(4.184)(10°C)= 418.4
Qw=
= -0.4184
0.02g Mg (
= 0.0008
-0.4184/0.0008= -523 kJ/mol
- (10mL)(4.184)(9°C)=376.56
Qw=
= -0.37656
0.02g Mg (
= 0.0008
-0.37656/0.0008= -470.7 kJ/mol
Step 6: Repeat steps 1-5 8 more times for a total of 9 trails changing the mass of Mg in step 4 every 3 trails from 0.02g ± 0.001g to 0.03g ± 0.001g to 0.04g ± 0.001g.
Data
Calculations:
When a sample of Mg dissolves in 10mL HCl, the temp increases. The following are the ΔH of the 9 trials:
Equation: q=mcΔT
Trial 1 0.02g ± .001g Mg
- (10mL)(4.184)(10°C)= 418.4
Qw=
= -0.4184
0.02g Mg (
= 0.0008
-0.4184/0.0008= -523 kJ/mol
- (10mL)(4.184)(9°C)=376.56
Qw=
= -0.37656
0.02g Mg (
= 0.0008
-0.37656/0.0008= -470.7 kJ/mol
- (10mL)(4.184)(7°C)= 292.88
Qw=
= -0.29288
0.02g Mg (
= 0.0008
-0.29288/0.0008= -366.1 kJ/mol
Average of trial 1 is 453.27 kJ/mol
Trail 2 0.03g ± .001g Mg
- (10mL)(4.184)(13°C)=543.92
Qw=
= -0.54392
0.03g Mg (
= 0.0012
-0.54392/0.0012= -453.3 kJ/mol
- (10mL)(4.184)(11°C)=460.21
Qw=
= -0.46021
0.03g Mg (
= 0.0012
-0.46021/0.0012= -383.5 kJ/mol
- (10mL)(4.184)(11°C)=460.21
Qw=
= -0.46021
0.03g Mg (
= 0.0012
-0.46021/0.0012= -383.5 kJ/mol
Average of Trial 2 is 406.77 kJ/mol
Trail 3 0.04g ± .001g Mg
- (10mL)(4.184)(16°C)=669.44
Qw=
= -0.66944
0.04g Mg (
= 0.0016
-0.66944/0.0016= -418.4 kJ/mol
- (10mL)(4.184)(15°C)=627.6
Qw=
= -0.6276
0.04g Mg (
= 0.0016
-0.6276/0.0016= -392.25 kJ/mol
- (10mL)(4.184)(17°C)=711.28
Qw=
= -0.71128
0.04g Mg (
= 0.0016
-0.71128/0.0016= -444.55 kJ/mol
Average of Trial 3 is 418.4 kJ/mol
Average of all ΔH for the 9 trials is -340.92 kJ/mol
Conclusion and Evaluation
The results depicted a small correlation between the enthalpy change in the reaction between Mg and HCl when different amounts of Mg are added to a constant amount of HCl. The average enthalpy change of the different masses of Mg are not consistently changing. When the amount of Mg shifts from 0.02g ± 0.001g to 0.03g ± 0.001g the average enthalpy changes from 453.27 kJ/mol to 406.77 kJ/mol but when it shifts form 0.03g ± 0.001g to 0.04g ± 0.001g the average enthalpy changes from 406.77 kJ/mol to 418.4 kJ/mol. Now the answer to the question -How is the enthalpy change of the reaction between Mg and HCl affected when different amounts of Mg are added to a constant amount of HCl? - Is there is an effect to the enthalpy change when different amounts of Mg are added but it is irregular and the change in the enthalpy isn’t steady in its rise or decline.
The experiment was done using different foam cups and a calorimeter and the amount of time that the chemicals temperatures were recorded were different. If I was to improve this experiment I would use the same kind of foam cups and lids for each trial and I would also measure the temperature for each chemical under a specific time limit which would be the same for each trial.
Investigation of Enthalpy Change When Mg is added to HCl
Kerolin Francois
Lab Report
IB Chemistry
Period 4
by
kmann561 (student)
