The mole fraction of co2 in a certain solution with h2o as the solvent is 3.6 × 10−4. what is the % mass of co2 in this solution?

Explanation:

1) Basis

Assume 100 moles of solution

2) Number of moles of CO₂ (solute)

3) Number of moles of H₂O (solvent)

4) Mass of solution

a) Mass = number of moles × molar mass

b) Mass of CO₂ = 0.036 mol × 44.01 g/mol = 1.584 g

c) Mass of H₂O = 99.964 mol × 18.015 g/mol = 1,800.85 g

d) Mass of solution = mass of solute + mass of solvent = 1.584 g + 1,800.85 g = 1,802.435 g

5) Percent mass of CO₂, %

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.

smooth muscle is composed of involuntary muscles found within the walls of organs and structures such as the esophagus, stomach, intestines, and blood vessels. those muscles push materials like food or blood through organs. unlike skeletal muscle, smooth muscle can never be under your control.