Record the following for each of the three trials
Question
1. Record the following for each of the three trials:
· Trial
1
a | Mass of the empty calorimeter (g)18.6g |
b | Initial temperature of the calorimeter (°C)21.5°C |
c | Maximum temperature in the calorimeter from the reaction (°C)35.0°C |
d | Calculate ΔT by subtracting (b) from (c) (°C) ΔT = Tmaximum – Tinitial35.0°C-21.5°C=13.5°C |
e | Mass of the calorimeter and its contents after the reaction (g)68.74g |
f | Calculate the mass of the contents of the calorimeter (g) by subtracting (a) from (e)68.74g-18.6g=50.14g |
g | Calculate the moles of Mg reacted (MW = 24.305 g/mole)?50mL of 1M HCI is 50/1000×1=0.05.15/24.305=.006g/mole |
· Trial 2
a | Mass of the empty calorimeter (g)18.6g |
b | Initial temperature of the calorimeter (°C)21.5°C |
c | Maximum temperature in the calorimeter from the reaction (°C)44.0°C |
d | Calculate ΔT by subtracting (b) from (c) (°C) ΔT = Tmaximum – Tinitial44.0°C-21.5°C=22.5°C |
e | Mass of the calorimeter and its contents after the reaction (g)68.83g |
f | Calculate the mass of the contents of the calorimeter (g) by subtracting (a) from (e)68.83-18.6=50.23 |
g | Calculate the moles of Mg reacted (MW = 24.305 g/mole).25/24.305=.010g/mole |
· Trial 3
a | Mass of the empty calorimeter (g)18.6g |
b | Initial temperature of the calorimeter (°C)21.5°C |
c | Maximum temperature in the calorimeter from the reaction (°C)52.9°C |
d | Calculate ΔT by subtracting (b) from (c) (°C) ΔT = Tmaximum – Tinitial52.9°C-21.5°C=31.4°C |
e | Mass of the calorimeter and its contents after the reaction (g)68.92g |
f | Calculate the mass of the contents of the calorimeter (g) by subtracting (a) from (e)68.92g-18.6g=50.32 |
g | Calculate the moles of Mg reacted (MW = 24.305 g/mole).35/24.305=.014g/mole |
2. Calculate the heat released into the solution for the 3 reactions, according to the formula:
qreaction= (Ccal * ΔT) + (mcontents* Cpcontents* ΔT) |
3.
Assume Cpcontents= Cpwater= 4.18 J/g °C
a | Trial 1 (J)(4.18J/g°C)(68.74g)(35.0°C-21.5°C)=3878.9982 J/g°C |
b | Trial 2 (J)(4.18J/g°C)(68.83g)(44.0°C-21.5°C)=6473.4615 J/g°C |
c | Trial 3 (J)(4.18J/g°C)(68.92g)(52.9°C-21.5°C)=9045.88784 J/g°C |
4. Find the molar heat of reaction for each experiment in units of kilojoules / (mole of Mg) by dividing the heat of reaction (converted to kJ by dividing by 1000) by the moles of Mg used.
a | Trial 1 (kJ/mol) |
b | Trial 2 (kJ/mol) |
c | Trial 3 (kJ/mol) |
5. Calculate and record the average molar heat of reaction from the three results: