How Do You Calculate the Empirical Formula of Magnesium Nitride?

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Discussion Overview

The discussion revolves around calculating the empirical formula of magnesium nitride based on given masses of magnesium and nitrogen. Participants explore the steps involved in determining the empirical formula, including the conversion of mass to moles and the establishment of ratios between the elements.

Discussion Character

  • Homework-related
  • Mathematical reasoning

Main Points Raised

  • One participant asks for guidance on calculating the empirical formula of magnesium nitride from given masses of magnesium and nitrogen.
  • Another participant suggests starting by converting the masses of magnesium and nitrogen into moles to find the ratios needed for the empirical formula.
  • A third participant explains the process of calculating moles and obtaining a ratio, noting that the ratio of magnesium to nitrogen is 1.5 to 1, which requires multiplication to achieve whole numbers for the empirical formula.
  • A later reply expresses gratitude and shares a personal anecdote about their chemistry background, indicating a transition to university studies.

Areas of Agreement / Disagreement

Participants generally agree on the method of converting mass to moles and finding ratios, but there is no consensus on the specific calculations or the initial steps, as one participant questions the subtraction of masses.

Contextual Notes

Some assumptions about atomic weights and the method of calculating moles are not explicitly stated, and the discussion does not resolve the initial query regarding the first step in the calculation.

Who May Find This Useful

Students studying chemistry, particularly those learning about empirical formulas and stoichiometry, may find this discussion relevant.

thomas49th
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Hi. I am having problems with finding the empirical formulae

What is the emprical formula of magnesium nitride if 0.72g of magnesium combines with 0.28g nitrogen?


So what would my first step be? Find magesuim... which would be 0.44g?
Can you take me through the steps?

Thx
 
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thomas49th said:
Hi. I am having problems with finding the empirical formulae

What is the emprical formula of magnesium nitride if 0.72g of magnesium combines with 0.28g nitrogen?


So what would my first step be? Find magesuim... which would be 0.44g?
Can you take me through the steps?

Thx
I would start by converting your Mg and N into moles. The basic idea is to look at the ratios of one substance to another to find the emiprical formula.

I don't know why you subtracted up there. Mass must be conserved, so if you start out with 0.72g and 0.28g, how much must you have after the reaction?
 
First calculate the number of moles of both of them by dividing each by their atomic weights.
Moles are obtained

Now divide each mole by the smallest mole obtained i.e. 0.02 mole of nitrogen, ratio obtained will be 1.5 of magnesium and 1 of nitrogen

as 1.5 is not a whole number multiply it by 2 to get a whole number and you will get as 3 and 2 respectivley. thus from this you can get that 3 moles of magnesium reacts with 2 moles of nitrogen to give magnesium nitride.

I hope this will help you out.
Regards
 
Hahaha thanks :D But a little late, I did my GCSE chemistry over 3 years ago and got my A - never said thank you hage567. Infact, I'm starting university tomorrow!

Thanks
Thomas :)
 

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