Youcant putagasinaweighingpanlikeyoudid thepennies

Info iconThis preview shows page 1. Sign up to view the full content.

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

Unformatted text preview: Oct 13‐15, as usual. 2 Exp 4 – Molar mass using the Dumas method MOLAR MASS: Defined as the mass of one mole of a substance. But how do you weigh a gas? You can't put a gas in a weighing pan like you did the pennies. So instead, we use a Dumas tube, which is a tube with a very narrow neck. – At room temperature, the tube is filled with air at atmospheric pressure. – The mass is that of the tube + air (blue dots) • When a volatile liquid (red) is placed in the tube, at first the liquid is in equilibrium with its vapor (red dots) and it also contains air. • As the tube is heated, the liquid vaporizes and the air is swept out of the tube. At temperatures above th...
View Full Document

Ask a homework question - tutors are online