How many moles of ammonium nitrate are present in 10.7 grams of ammonium nitrate? Thus how many...

Question:

How many moles of ammonium nitrate are present in 10.7 grams of ammonium nitrate? Thus how many grams of ammonium nitrate is needed to make exactly one mole of ammonium nitrate?

Molar Mass of a Molecule

If the molar mass of all the atoms present in a molecule is added together, then the mass so obtained for that molecule is called the molar mass of the molecule. If we count the number of molecules of this much mass, then the molecule will number 1 mole.

Answer and Explanation:

We are given:

  • {eq}m {/eq} = Mass of ammonium nitrate = 10.7 g

Let us assume:

  • {eq}M {/eq} = Molar mass of ammonium nitrate
  • {eq}n {/eq} = Number of moles of ammonium nitrate

The chemical formula of ammonium nitrate is {eq}NH_4NO_3 {/eq}.

So, the molar mass of ammonium nitrate is given by:

{eq}M = 1\times 14\ g+ 4\times 1\ g+ 1\times 14\ g+3\times 16\ g = 80\ g {/eq}

We know {eq}\textrm{Number of moles}=\dfrac{\textrm{Given mass}}{\textrm{Molar mass}}\\ \therefore n = \dfrac{m}{M}\\ \Rightarrow n = \dfrac{10.7\ g}{80\ g/mol}\\ \Rightarrow n = 0.134\ mol {/eq}

Hence, the number of moles of ammonium nitrate in the given mass is 0.134 mol.

Since the given mass of ammonium nitrate is 10.7 g and molar mass of it 80 g. So, the mass of ammonium nitrate needed to make it 1 mole is {eq}(80\ g-10.7\ g) = 69.3\ g {/eq}.

Hence, 69.3 g of ammonium nitrate is needed to make exactly one mole of ammonium nitrate.


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What is Molar Mass? - Definition, Formula & Examples

from General Studies Science: Help & Review

Chapter 27 / Lesson 24
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