Use the data in appendix 2 to calculate the value of standard enthalpy change for the following reaction at 298K N2O4 (g) = 2NO2 (g) what is its value at 350K? State any assumptions used in your calculation. Appendix two states that the standard molar enthalpy of formation for NO2 (g) is 33.9 kJ/mol and the standard molar enthalpy of formation for N2O4 is 9.7 kJ/mol. I believe the correct answer is 58.1 kJ/mol, but I don't know the assumptions and I'm not sure if the answer would change for the different temperatures.

1. the question asks the most appropriate, which seems to rule out "all of the above." your choice appears to be the correct one.

2. the protocol described is good for identifying correlation, but not cause and effect. for cause/effect, you need to devise a protocol that will assign the treatment (or not) to groups that have essentially the same "demographics" with respect to all the other variables. your choice regarding control group seems appropriate. random assignment of treatment (choice d) may be appropriate also. (i think you can argue that b and d are just different descriptions of the same method.)

3. d will randomize the birds, but may not guarantee there are 10 in each group. e will do both, so seems the better choice.

comment on question 2

based on the problem statement, it seems clear that confident, attentive drivers are more likely to use daytime running lights. so, the protocol might need to be devised in such a way that the lights would be turned on or off without the driver's knowledge. (an attentive driver will figure it out.) assigning a confident, attentive driver to a group required to drive without running lights might mess with his/her confidence and attentiveness. you don't want your experiment to do that. (nor do you want the experiment to subject a driver to greater risk of accident as a consequence of driving without running lights.) experiments involving human safety are always problematic.

put the answers   and i could answer.