Question

In a laboratory experiment, students synthesized a new compound and found that when 11.09 grams of the compound were dissolved to make 180.9 mL of a diethyl ether solution, the osmotic pressure generated was 3.88 atm at 298 K. The compound was also found to be nonvolatile and a non-electrolyte. What is the molecular weight they determined for this compound

Answer 1

The molecular weight of this compound is 386.4 g/mol

Step-by-step explanation:

Step 1: Data given

MAss of the compound = 11.09 grams

Volume of diethyl ether = 180.9 mL

Osmotic pressure = 3.88 atm

Temperature = 298 K

The compound = nonvolatile and non-electrolyte

Step 2: Calculate molar concentration

π = i*M*R*T

⇒with π = the osmotic pressure = 3.88 atm

⇒with i = the van't Hoff factor = 1

⇒with C = the molar concentration = = TO BE DETERMINED

⇒ with R = the gas constant = 0.08206 L*atm/mol*K

⇒with T = 298 K

C = 3.88 / (0.08206*298)

C = 0.1587 M

Step 3: Calculate moles compound

C = moles / volume

moles = 0.1587 M * 0.1809 L

Moles compound = 0.0287 moles

Step 4: Calculate molecular weight of the compound

Molar mass = mass / moles

Molar mass compound = 11.09 grams / 0.0287 moles

Molar mass compound = 386.4 g/mol

The molecular weight of this compound is 386.4 g/mol