Calculate the concentration of benzoyl peroxide required to prepare polystyrene with a number-average molar mass of 750 kg mol−1 by bulk polymerization at 60 °C. Assume: (i) the initiator is 60% efficient; (ii) the rate coefficients for initiator dissociation, propagation and termination are, respectively, 2 × 10−6 s−1, 341 dm3 mol−1 s−1 and 4 × 107 dm3 mol−1 s−1; (iii) the density of styrene at the polymerization temperature is 0.88 g cm−3; and (iv) that termination by disproportionation, and chain transfer to initiator and monomer, are negligible. Radical Polymerization 119 (b) Calculate initial values of (i) the radical concentration and (ii) the rate of bulk polymerization expected for bulk polymerization

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.

if you mean hydrogen and oxygen then water is the product

they are made of gases.

they have a spherical shape.

they make energy through fusion.