How many molecules of carbon dioxide are created when 16 molecules of propane react in the following unbalanced equation?
C3H3 +02— CO2+ H20

48 molecules of CO₂

Explanation:

I think you made a mistake in your question.  The formula for propane is C₃H₈, not C₃H₃.  But, I will give you the answer for both cases.

For C₃H₃:

First you have to balance the equation.

4 C₃H₃  +  15 O₂  ⇒  12 CO₂  +  6 H₂O

Next, you need to use the mole ratios between C₃H₃ and CO₂ to find the amount of molecules of CO₂ you will produce with the given amount of C₃H₃.

(16 mol's C₃H₃) × (12 mol's CO₂/4 mol's C₃H₃) = 48 mol's CO₂

You will get 48 molecules of CO₂.

For C₃H₈:

Balance the equation.

C₃H₈  +  5 O₂  ⇒  3 CO₂  +  4 H₂O

Use the mole ratios between C₃H₈ and CO₂.

(16 mol's C₃H₈) × (3 mol's CO₂/1 mol's C₃H₈) = 48 mol's CO₂

You will get 48 molecules of CO₂ for this equation as well.

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.