What is the density of 53.4 wt aqueous naoh?

Missing question: what is the density of 53.4 wt% aqueous NaOH if 16.7 mL of the solution diluted to 2.00L gives 0.169 M NaOH?

Answer is: density is 1.52 g/mL.

c₁(NaOH) = ?; molarity of concentrated sodium hydroxide.

V₁(NaOH) = 16.7 mL; volume of concentrated sodium hydroxide.

c₂(NaOH) = 0.169 M; molarity of diluted sodium hydroxide.

V₂(NaOH) = 2.00 L · 1000 mL/L = 2000 mL; volume of diluted sodium hydroxide.  

Use equation: c₁V₁  = c₂V₂.

c₁ = c₂V₂ / V₁.

c₁ = 0.169 M · 2000 mL / 16.7 mL.

c₁(NaOH) = 20.23 M.

m(NaOH) = 20.23 mol · 40 g/ml.

m(NaOH) = 809.53 g.

The mass fraction is the ratio of one substance (in this example sodium hydroxide) with mass to the mass of the total mixture (solution).

Make proportion: m(NaOH) : m(solution) = 53.4 g : 100 g.

m(solution) = 1516 g in one liter of solution.

d(solution) = 1516 g/L = 1.52 g/mL.

the correct name for the n3 ion is azide. azide is a polyatomic anion with a -1 charge and is written as n3 -1. it consists of three nitrogen atoms bonded together. hope i . let me know if you need anything else.

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.