A dichotomous key is an important scientific tool, used to identify different organisms, based the organism's observable traits. Dichotomous keys consist of a series of statements with two choices in each step that will lead users to the correct identification.
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Answer:
Highest boiling point - 0.43 m Urea
Second highest boiling point - 0.20 m NiSO4
Third highest boiling point - 0.19 m NH4I
Lowest boiling point - 0.17 m NH4NO3
Explanation:
We know that;
ΔT = kb m i
Where;
ΔT = boiling point elevation
kb = boiling point constant
m = molality of the solution
i = Van't Hoff factor
For NiSO4 , NH4I and NH4NO3 , the Van't Hoff factor, i = 2
But for Urea, the Van't Hoff factor, i = 1
We also have to consider both the values of the molality and Van't Hoff factor , knowing that a higher molality and a higher Van't Hoff factor leads to a higher ΔT and consequently a higher boiling point.
This facts above account for the arrangement of substances shown in the answer.
Answer:
Left
Explanation:
Metals are located on the left of the periodic table, and nonmetals are located on the upper right. They are separated by a diagonal band of semimetals.
First,
Moles of HBu = Volume per liter * moles of HBu/ liter
= 25ml/1000 * 0.15 = 0.00375 moles
moles of NaOH = volume per liter * moles of NaOH/liter
= 1 ml/1000 * 0.15 = 0.00015 moles
according to this equation:
HBu + NaOH → H2O + NaBu
when 1 mol of NaOH gives 1mol of HBu
So 0.00015 of NaOH will give 0.00015 mol of HBu
∴moles of HBu which remains = 0.00375- 0.00015 = 0.0036 moles
∴moles of Bu- produced = 0.00015 moles
when the total volume = 0.025 + 0.026 =0.051 L
[HBu] = 0.0036moles / 0.051 L = 0.071 moles
[Bu] = 0.00015 / 0.051L = 0.0029 moles
when Ka = [H+] [Bu] / [HBu]
1.5x10^-5 = [H+] (0.0029) /(0.071)
∴[H+] =1x10^-6 / 0.076 = 1.5 x 10^-5
∴PH = -㏒[H+]
= - ㏒ 1.5x10^-5
= 4.81
