Determining the molecular mass of a gas

# Determining the molecular mass of a gas - Christina Wong AP...

This preview shows pages 1–2. Sign up to view the full content.

Christina Wong AP Chemistry 4 th hour 3/31/2010 Determining the Molecular Mass of a Gas I. Purpose The purpose of this lab was to determine the molecular mass of a substance from measurements of the density of its vapor. II. Observations and Data Mass of flask + cap 83.96 g Mass of flask + cap + condensate 84.34 g Volume of flask (V 1 ) 125 mL Temperature of water, (T 1 ) 98 C = 371 K Barometric pressure 29.98 inHg = 761.5 mmHg III. Calculations 1. Find the mass of the condensed vapor: Mass = part b – part a Mass = 84.34 – 83.96 = 0.38 g 2. Find the volume of the vapor at STP: V 2 =V 1 x P 1 x T 2 /P 2 x T 1 V 2 =125mL x 761.5 mmHg x 273 K / 760 mmHg x 371 K V 2 = 92.16 mL 3. Find the molecular mass of the gas sample Molecular mass = m (g) x 22.4 (L/mole) / V 2 (L) Molecular mass = 0.38 g x 22.4 L/mole / 0.09216 L Molecular mass = 92.36 g IV. Conclusions and Questions 1. Using the molecular formula supplied by the teacher, calculate the actual molecular mass of the unidentified substance. The actual molecular mass of ethanol (C

This preview has intentionally blurred sections. Sign up to view the full version.

View Full Document
This is the end of the preview. Sign up to access the rest of the document.

## This note was uploaded on 12/03/2011 for the course CHEM BIO P 101 taught by Professor Kk during the Spring '11 term at Rochester.

### Page1 / 2

Determining the molecular mass of a gas - Christina Wong AP...

This preview shows document pages 1 - 2. Sign up to view the full document.

View Full Document
Ask a homework question - tutors are online