Research Question: How does the reactivity of a Metal affect the enthalpy change for a reaction?
Aim:
To investigate how reactivity’s of various metals (Fe, Mg, Zn, Cu and Mn) affect the enthalpy change of the solution when it reacts with 25cm3 Copper II Sulphate.
Theory: Specific heat capacity is the amount of energy needed to raise the temperature of one gram of a substance by 1 degree Celsius. Different materials absorb different amount of heat when their temperature rises by one degree Celsius. Therefore, every material has a different specific heat capacity. Metals usually heat up very easily because they have a low specific heat.
Equations
Mn(s) + CuSO4 (aq) MnSO4 (aq) + Cu (s)
Fe(s) + CuSO4 (aq)
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Data Table 2:
Table showing the average temperature (oC) (±0.5oC)per increment for the five metals reactions with Copper II Sulphate:
Time (s) (±0.01s) Temperature (oC) (±0.5oC) Copper II (Cu) Manganese (Mn) Iron (Fe) Zinc (Zn) Magnesium (Mg)
0 25 25.3 25.0 25.0 25.0
30 25 25.3 30.7 25.0 25.0
60 25 64.3 33.7 32.7 64.7
90 25 75.7 35.3 34.0 92.7
120 25 78.3 36.7 35.3 91.0
150 25 77.7 37.0 36.0 88.3
180 25 76.3 37.0 36.7 86.7
210 25 74.3 39.0 38.0 83.3
240 25 72.3 39.7 38.3 81.3
270 25 70.7 40.0 39.3 79.0
300 25 69.0 40.7 40.0 78.0
330 25 41.0 40.7 77.0
360 25 41.0 43.3
390 25 41.7 45.0
420 25 42.0 47.0
450 25 42.0 48.3
480 25 42.0 48.7
510 25 410 49.0
540 50.0
570 49.3
600 49.0
Data
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Temperature (Magnesium)
25oC ±0.5 = 0.5/25 x 100= 2%
Δ Temperature: (Tf – Ti)
0.5/98.82 x 100 = 0.5%
55.7 – 25 = 73.8
2% + 0.5% = 2.5% (of 73.8) = ±3.38oC
Similarly evaluate other uncertainties
By plugging in these values in the formula we can find energy released by the reaction:
Q Magnesium= (25g) x (4.18) x (73.8) = 7714.2 Joules (J) = 7.714 Kilojoules (kJ)
Absolute Uncertainty:
Volume:
0.3/25 x 100 = 1.2%
Energy uncertainty = 1.2% + 2.5% = 3.7% (of 7.71 kJ) = ±0.29 kJ
Using the average mass of every metal used, we can find the number of mols through the formula n=