4.00 grams of an unknown monoprotic acid is titrated with 0.75 m naoh. it takes 88.81 ml of naoh to completely neutralize the acid. what is the molecular weight of the acid?

The molecular weight of the acid is 60.05 g/mol

Explanation:

Let's state the balanced chemical equation to represent the neutralization reaction:

NaOH + HAc → NaAc + H2O

where HAc is the representation of the monoprotic acid. As we can see, the relationship between the base and the acid is 1:1, that is 1 mole of NaOH reacts with 1 mole of the monoprotic acid HAc. So, let's calculate the moles of NaOH that where present in the 88.81 mL aliquot used to neutralize the acid:

1000 mL 0.75 moles of NaOH

88.81 mL --- x = (88.81 mL × 0.75 moles)/1000 mL = 0.0666075 moles NaOH

As we stated before, 1 mole of NaOH will react with 1 mole of HAc, so 0.0666075 moles of NaOH will reacted with 0.0666075 moles of the acid. Having said that, because we already know the mass of the acid, we are able to determine the molecular weight of it:

0.0666075 moles of HAc 4.00 g

1 mole of HAc x = (1 mole × 4.00 g)/0.0666075 moles = 60.05 g/mole

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.