Law enforcement uses a quick and easy test to detect the presence of the illicit drug PCP by reacting it with potassium iodide. The PCP will form a crystalline solid with a long branching needle-like structure with KI. What is the molarity of KI in a stock solution prepared by dissolving 390.1 g of KI to a total volume of 140.0 mL?

16.79 M

Explanation:

Given data

First, we will calculate the moles of KI, considering its molar mass is 166.00 g/mol.

390.1 g × (1 mol/166.00 g) = 2.350 mol

The molarity of KI is:

M = moles of solute / liters of solution

M = 2.350 mol / 0.1400 L

M = 16.79 M

hey there!

mass = 6.75 g

volume =   9 cm³

therefore:

d = mass / volume

d   = 6.75 / 9

d = 0.7 g/cm³

answer b

substituting a hydrogen atom with a halogen in a hydrocarbon:

- the single bond remains single. a is wrong.

- the bond with hydrogen is as strong as with a halogen. c is wrong

- a hydrocarbon is saturated if there is no double bond. we do not know that so d is wrong.

- carbon will always have four valence electrons. e is wrong.

by elimination, the correct answer is b. the boiling point of the new compound increases.