What is the molarity of 2.0 liters of an aqueous solution that contains 0.50 mol of potassium iodide

[KI] = 0.25 M

Explanation:

Solute: KI

Mass of solute: 0.50 mol . 166 g / 1mol = 83 g

Our solution volume is 2L

Molarity is a kind of concentration, defined as the moles of solute contained in 1L of solution. It is the most common concentration for all solutions while there are any other kind, for example molality, mole fraction or ppm.

In this case molarity (mol/L) is 0.5 mol /2L = 0.25 M

In conclussion, solution is 0.25 molar whichs is the same to say, that 0.25 moles of potassium iodide are contained in 1L of solution.

With the data given, we can also make a rule of three:

2L of solution contain 0.5 moles of KI

Then, 1L of solution may contain (0.5 . 1) /2 = 0.25 moles of Ki

0.25mol/L

Explanation:

Data obtained from the question include:

Mole of solute (KI) = 0.50 mol

Volume of solution = 2L

Molarity =?

Molarity is simply the mole of solute per unit litre of the solution. It is represented mathematically as:

Molarity = mole of solute /Volume of solution

Molarity = 0.50mol/2L

Molarity = 0.25mol/L

Therefore, the molarity of the solution is 0.25mol/L

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.

o conteúdo de calor de um sistema é igual à entalpia apenas para um sistema que é constante