You have the equations:

2H2O(l)→2H2(g)+O2(g), △H=572 kJ

2N2(g)+3H2(g)→2NH3(g), △H=−138 kJ

2NO2(g)+7H2(g)→2NH3(g)+4H2O(l), △H=−1.18×103 kJ 2NO2(g)→2N2(g)+2O2(g), △H=□

What is the missing △H ?

−1.38×103 kJ

+99.0 kJ

+1.38 × 10³ kJ

−138 kJ

•what conclusions can you make about the relationship between the volume of a gas and its temperature? • what conclusions can you make about the relationship between the volume of a gas and its pressure? • what possible variables have you not accounted for? as you did the procedures, is it possible that the atmospheric pressure may have changed? if it did change over the course of your experiment, then how would your results have been affected?