Suppose a 2.95 g of potassium iodide is dissolved in 350. ml of a 62.0 m m aqueous solution of silver nitrate. calculate the final molarity of iodide anion in the solution. you can assume the volume of the solution doesn't change when the potassium iodide is dissolved in it. be sure your answer has the correct number of significant digits

Answer : The final molarity of iodide anion in the solution is 0.0508 M.

Explanation :

First we have to calculate the moles of and .

Molar mass of KI = 166 g/mole

and,

Now we have to calculate the limiting and excess reagent.

The given chemical reaction is:

From the balanced reaction we conclude that

As, 1 mole of KI react with 1 mole of

So, 0.0178 mole of KI react with 0.0178 mole of

From this we conclude that, is an excess reagent because the given moles are greater than the required moles and KI is a limiting reagent and it limits the formation of product.

Now we have to calculate the moles of

From the reaction, we conclude that

As, 1 mole of react to give 1 mole of

So, 0.0178 moles of react to give 0.0178 moles of

Thus,

Moles of AgI = Moles of anion = Moles of cation = 0.0178 moles

Now we have to calculate the molarity of iodide anion in the solution.

Therefore, the final molarity of iodide anion in the solution is 0.0508 M.

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.