Posted by Narash on Friday, March 25, 2011 at 3:32pm.
Calculation of )Hf0 for Mg2+(aq.)
1. Assume the heat capacity of the final solution is 3.92 J K-1 g-1. Using the mass of the HCl
solution, calculate qcontents from equation (4.6). Calculate qsystem from equation (4.5).
2. Calculate the moles of Mg2+ produced, nrxn. Be sure to identify the limiting reagent in the
3. Calculate the molar enthalpy change, )H0 rxn, for reaction (4.19). This is the same as )H0f for
Mg2+(aq.).Calculation of )Hf0 for MgO(s)
Calculation of delta Hf for MgO(s)
1. Again, assume the heat capacity of the final solution is 3.92 J K-1 g-1. Calculate qcontents and
2. Calculate the number of moles of Mg2+ (aq.) produced, nrxn.
3. Calculate the standard molar enthalpy change for reaction (4.20).
4. Average the values for )H0 rxn for part I and average the values for )H0
rxn for part II. Using these average values, calculate )H0f of MgO(s).
1. Why are both the mass and the volume of the hydrochloric acid solution recorded?
2. In this experiment it was assumed that the calorimeter neither absorbed nor released heat
(i.e., qcalorimeter = 0), but this is almost certainly not the case. Would the measured value of
)H0f (Mg2+(aq.)) be more or less exothermic if the calorimeter absorbed heat (that is, if
qcalorimeter > 0)? Explain why.
3. Explain why )H0rxn, for reaction (4.19) is the same as )H0f for Mg2+(aq.).
4. Use tabulated standard molar enthalpies of formation (from the textbook) to calculate )H0
for the following reactions:
1. 2NO(g) + O2(g) v 2NO2(g)
2. 2H2S(g) + 3O2(g) v 2SO2(g) + 2H2O(g)
3. Fe2O3(s) + 3CO(g) v Fe(s) + 3CO2(g)
5. Calcium sulphate reacts with carbon (in the form of graphite) according to the reaction:
CaSO4(s) + 1/2C(s, graphite) v CaO(s) + SO2(g) + 1/2CO2(g)
When 204.2 g of CaSO4(s) reacts with excess graphite at 298.15 K and 1 atm pressure, 456
kJ of heat are absorbed. Calculate the standard molar enthalpy of formation of CaSO4(s).
Magnesium and hydrochloric
mass of calorimeter+HCl/g =193.89g
mass of calorimeter/g=134.24g
mass og HCl/g=59.65g
mass of 50 mL beaker+Mg/g=30.7885g
mass of 50mL beaker/g=30.5655g
mass of Mg/g 0.2230g
final temp 30.1
mass of calorimeter+HCl/g =191.85g
mass of calorimeter/g=132.04g
mass og HCl/g=59.81g
mass of 50 mL beaker+Mg/g=31.7475g
mass of 50mL beaker/g=31.574g
mass of Mg/g 0.1727g
final temp 30.1
Part 2 Magnesium oxide+Hydrochloric
mass of calorimeter+HCl/g =192.49g
mass of calorimeter/g=131.26g
mass og HCl/g=61.23g
mass of 50 mL beaker+Mg/g=32.2601g
mass of 50mL beaker/g=31.5502g
mass of Mg/g 1.2601g
final temp 28.0
mass of calorimeter+HCl/g =190.56g
mass of calorimeter/g=131.52g
mass og HCl/g=59.04g
mass of 50 mL beaker+Mg/g=32.2486g
mass of 50mL beaker/g=31.5532g
mass of Mg/g 0.6954g
final temp 28.0
I am greatly appreciate your help.. Sad
Answer this Question
Chemistry - Help with lab report Need Help finishing my lab report.KNOWN VALUES ...
Chemistry - Suppose that 50.0 mL of a 0.250 M HCl solution is mixed with 50.0 mL...
chemisrty - A 50.0 mL solution of 1.2 M HCl at 24.1C is mixed with 50.0 mL of 1....
Grade 12 chemistry - This is the second reaction: HCl(aq)+NaOH(aq)-->NaCl(aq...
Chemistry - Consider the following reaction AgNO3 (aq) + NaCl (aq) → AgCl...
chemistry - If 15.0 mL of a 1.5M HCl solution at 22.5 degrees C is mixed with 25...
chemistry - 1. a) 50ml of water at 46.9°C were mixed with 50ml of water at 25.1°...
Chemistry 1 - A dilute solution of hydrochloric acid with a mass of 614.86 g and...
Chemistry - The specific heat of a solution is X J/g*degreesC and its density is...
chemistry - When 0.667 g of Ca metal is added to 200.0 mL of 0.500 M HCl(aq), a ...