1) what type of solution (saturated or unsaturated ) is present for Pb(NO3)2 if at approximately 25 degrees c ,65 grams of the substance are present in the 100 grams of H2O

2)40 grams of KCl are dissolve in 100 grams of H2O at 10 degrees c how many grams will not dissolve

3)how many grams of H2O are needed to dissolve 50 grams of KClO3 at 70 degrees C

4)how many grams of K2Cr2O7 will dissolve in 75 grams of H2O at 90 degrees C

5) 59 grams of CaCl2 are dissolve in 100 grams of water at approximately 25 degrees c how many more grams of CaCl2 must be added to saturate the solution

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.

it is stable as it is in group 0 which have full outer shells of electrons

the dissociation of nickel hydroxide is follows:

the concentration of hydroxide ion is

the equilibrium constant value of nickel hydroxide is = 6.1 * 10^-^1^6 and thus equilibrium equation can be written as:

thus, concentration of ni is 0.23 * 10^-^4 mol /l