9. calculate the standard enthalpy of the 3rd reaction using the given data: a, h° = +52.96 kj/mol afh= -483.64 kj/mol h2s)+i202 hi 2 h2g)+o2ig)2 h2o() 4 hig+o2lg)2 12)+2 h2o(e (1) (2) (3) a, h° =? 10. calculate the internal energy change for reaction (3) in the previous problem.

-586.56 kJ/mol is the standard enthalpy of the 3rd reaction.

Explanation:

...[1]

...[2]

..[3]

The unknown standard enthalpy of third reaction can be calculated by using Hess's law:

The law states that 'the heat absorbed or evolved in a given chemical equation is the same whether the process occurs in one step or several steps'.

[2] - 2 × [1] = [3]

The standard enthalpy of the 3rd reaction is -586.56 kJ/mol.The negative sign indicates that energy is released during this reaction.

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.

lol for the pointsss