For each of the scenarios, determine if the ionic strength of the solution would increase, decrease, or not change. a. If a solution of HNO3 were added to a solution of KOH , the ionic strength of the KOH solution would:

1. Increase
2. Decrease
3. Not change

b. If a dilute solution of KOH were added to a solution of CaCl2 (Ca(OH)2 (s) is formed), the ionic strength would:
1. Increase
2. Decrease
3. Not change

Increase

Decrease

Explanation:While in solution, ionic substances produce ions. The ions in solution determine the conductivity of the solution.

The ionic strength of a solution shows the concentration of ions in a given solution. The more the number of ions in the solution, the greater the ionic strength of the solution and vice versa.

When HNO3 is added to a solution of KOH, the number of ions in the solution increases and so does the ionic strength of the solution.

When KOH is added to a solution of CaCl2 then Ca(OH)2 is formed. The formation of a solid precipitate decreases the concentration of ions in solution as well as the ionic strength of 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.

the answer is c.the valence of the atoms combine .