2. Caleulate the molecular weight of Freon-12, if 122.70 liters of its vapor at

Question

2. Caleulate the molecular weight of Freon-12, if 122.70 liters of its vapor at 200,00'C and 790.00 mm Hg has a mass of 397.00 g. Show your work. 3. Suppose a student performs this experiment and obtains a molecular weight of 70 g/mol for isopropyl alcohol. Give valid sources of error for what could have caused the molecular weight to be higher than expected. 4. Suppose a student performs this experiment and obtains a molecular weight of 65 g/mol for t-butyl alcohol. valid sources of error for what could have caused the molecular weight to be lower than expected.

Explanation / Answer

2. We are given the mass of Freen as 397.00 g. So in order to find out the molar mass, we need to find out number of moles. Given the pressure, volume and temperature, we can find out the number of moles using:

PV = nRT, where

P = 790.00 mm of Hg, converiting to atm we get 790 mm Hg * (1 atm/760 mm Hg) = 1.0394 atm

V = 122.70 L

R = 0.08205 Latm/mol.K

T = 200.0 deg C = 200.00 + 273.15 K = 473.15 K

now plugging into the eqations for n = PV/RT

n= (1.0394 atm *122.70 L) / (0.08205 Latm/mol.K * 473.15 K)

n = 3.2851 moles of Freon

molar mass of  Freon = mass / moles = 397.00 g/ 3.2851 moles = 120.85 g/mol

Related Questions

Navigate

• Browse (All)
• Browse 2
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.