How many grams of manganese (IV) oxide are needed to make 5.6 Liters of a 2.1 solution? (solve for moles then convert to grams)

We are Given:

Final volume of the solution = 5.6 L

Concentration of the solution = 2.1 M

Moles of Manganese (IV) Oxide required:

Molar mass of Manganese (IV) Oxide = 87 grams/mol

since the concentration is 2.1 M, we will need 2.1 moles of Manganese Oxide for every 1L of the solution

Number of moles required = Molarity * Volume required

Number of moles required = 2.1 * 5.6 = 11.76 moles

Mass of Manganese (IV) Oxide required:

mass = molar mass * number of moles

Mass = 11.76 * 87

Mass = 1023.12 grams of Manganese (IV) Oxide

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.

solute : a solute is a substance that is dissolved in another substance is known as a solvent. it is mixed with a special mixture know as homogeneous mixture.

solvent: a solvent is a substance that dissolved a solute, which results in a solution is known as solvent.