[Shehezaada]

Hey guys...quick question!

We've done a lab for the molar enthalpy of the combustion of Magnesium in air. I did all the calculations and stuff...ya know, got -626kJ/mol (using Hess's Law)...but there's a question in the synthesis

Suggest an experimental technique that could be used to determine the enthalpy of combustion of magnesium directly.

No idea on this one! Tried googling it...gettin nothing...any help would be appreciated!

Shehezaada

[mike]

A good way to test molar enthalpy directly is to how much a sample can heat up a known amount of water.

You could measure the temperature of a known amount of water, then burn the magnesium under the water and measure what the temperature increase is. Then knowing the specific heat of water you could work out the enthalpy of combustion.

Of course there are limitations to this procedure in that a lot of the energy relesed by the magnesium is lost as light and a lot of the "heat" from the magnesium is lost to the surroundings rather than going to heat the water.

[Shehezaada]

wow mike...how cool an idea is that!

that's brilliant man, thanks, and i'm just gonna put the link in my lab to give ya credit for it!