If you start with 3 moles of sodium and 3 moles of chlorine to produce sodium chloride, what is the limiting reagent?(You will need to balance the equation first.)
Na + Cl2 -> NaCl A. They are equal B. Na C. Cl2 D. NaCl

B. Na

Explanation:

Once balanced you get 2Na + Cl₂ ⇒ 2NaCl. Sodium is the limiting reagent because it would produce the smallest amount of the product (NaCl)–while chlorine is the excess reagent. Based off of the Na in the balanced equation, it would produce 3 moles of NaCl, and for Cl₂ it would produce an excess of 6 moles of NaCl. [It'd be wise to utilize stoichiometric factors to get a good grasp of this]

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.

the increase of protons   hope this