The answer is most definitely “A”
Answer:
1.62
Explanation:
From the given information:
number of moles of benzamide
= 0.58 mole
The molality =
= 0.6837
Using the formula:
where;
dT = freezing point = 27
l = Van't Hoff factor = 1
kf = freezing constant of the solvent
∴
2.7 °C = 1 × kf × 0.6837 m
kf = 2.7 °C/ 0.6837m
kf = 3.949 °C/m
number of moles of NH4Cl =
= 1.316 mol
The molality =
= 1.5484
Thus;
the above kf value is used in determining the Van't Hoff factor for NH4Cl
i.e.
9.9 = l × 3.949 × 1.5484 m
l = 1.62
A polymer is a really long chain of smaller molecules (monomers). It's similar to a chain of paper clips because all of the little monomers will attach to each other, forming a long strain.
The book<span> documented the detrimental effects on the environment—particularly on birds—of the indiscriminate use of pesticides. -A</span>
<u>Answer:</u>
The correct answer option is a. Selenium (Se).
<u>Explanation:</u>
From the given answer options, Selenium (Se) is the only element which is a non metal.
It has the atomic number 34 with atomic weight 78.96. It is a member of the sulfur group of the non metallic elements and falls in period 4 of the Periodic table.
Selenium has non metallic properties which are intermediate between the elements that lie above and below it in the Periodic table.