Multistep Calculations

1.	Sulphuric acid reacts with limestone, calcium carbonate, in the following reaction:

CaCO3 (s) + H2SO4 (l) → CaSO4 (s) + H2O (l) + CO2 (g)  

(i)	Using the information in Appendix C6 (pg 799) in you text, determine the enthalpy change for reaction above.
(ii)	Determine the enthalpy change that occurs if 156.9 g of calcium carbonate reacts with excess sulphuric acid.
(iii)	Determine the temperature change that would occur on 556.9 mL of water. 

2.	The  combustion of 0.2500 g of phosphorus trichloride, produces POCl3,  results in the temperature of 100.0 mL of water to rise 3.44oC. Using this information and information in Appendix C6, determine the molar enthalpy of formation for POCl3.

3.	Dinitrogen tetraoxide forms natural through the synthesis reaction of two nitrogen dioxide molecules according to the equation below:
2 NO2 (g) → N2O4 (g) 

The above reactions was determined to have a molar enthalpy of ∆H0 = - 57.20 kJ/mol NO2. Using this information determine:
(i)	The standard enthalpy of formation for dinitrogen tetraoxide.
(ii)	How many grams of nitrogen dioxide has to undergo the above conversion in order to raise the temperature of 50.7 mL of water from 56.7oC to 112oC.