How does your experimental value (0.00538 moles) compare to the actual molar mass of magnesium? Please provide a clear explanation.

Well, I'm assuming you calculated the number of moles of magnesium from your experiment.

You stated that you noticed that your experimental value is substantially less than the actual molar mass of magnesium. This usually happens in experiments because of many experimental errors.

So you should explain what part of the experiment that you might have done wrong or what factors (ie environmental such as light, air) that may have affected your results.

After explaining your mistakes, you could perhaps propose any solutions you have to that problem.

So obviously I don't know what experiment you are doing but I can give you an example. I did a practical on the heat of combustion of a series of different types of liquids (pentanol, hexanol). Now I had to find what was the heat of combustion for my liquids and my experimental values were way off from the actual values.

So to explain why, I said that because I couldn't conserve all the heat produced by oils so one way I could solve this problem was to have a heat shield surrounding my apparatus to conserve heat.

(this is what I can think off the top of my head)

Well, since you got a mass of #"24.3040 g"# for magnesium, and #"0.00538 mols"#, you can then compare it to the molar mass of magnesium.

Your value is

#"24.3040 g"/"0.00538 mols" = "4517 g/mol"#

which is far off from the molar mass it should be, #"24.305 g/mol"#. I assume you did not give the correct mass, and that the molar mass should have been #"24.3040 g/mol"#...

I suspect there was a mix-up in your data. If that is really a mass in #"g"#, then you should simply state that you were far off the true value, much more than #100%# error.

There are very few (if any) points deducted for not getting the correct value. It's not something you should be held accountable for.

You should be able to explain why you are this far off, however, and that will be left to you, because you have your data and we don't.