Question

Determination of Molecular Weight by Gas Density Measurements one of the simplest method for determining molecular weight is based on what?

Answer 1

The molecular weight determination based on gas density measurements is primarily achieved by using the ideal gas law to calculate the molar mass of an unknown gas, after measuring its mass and volume under known pressure and temperature conditions.

Step-by-step explanation:

The simplest method for determining molecular weight based on gas density measurements involves using the ideal gas law and understanding the relationship between molar mass, volume, and density. The ideal gas law can be used to calculate the molar mass of an unknown gas once the mass and volume of that gas have been determined, and the temperature and pressure conditions are known.

Here's a step-by-step explanation of how this is done:

1. Perform a chemical reaction to produce the gas, then collect and measure its mass and volume.
2. Use the known values of temperature and pressure, alongside the ideal gas law (PV = nRT), to find the molar volume.
3. With the molar volume, calculate the density of the gas using the formula density = mass/volume.
4. By rearranging the formulae, you can then determine the molecular weight of the gas.

For example, if you have a gas density of 0.761 g/L at STP (standard temperature and pressure), you would use this density along with the molar volume of a gas at STP (22.414 L/mol for an ideal gas) to find the molar mass of the gas.