Question #f69cb

To solve this question, we need to know the number of moles equivalent to the 35 g of `N_2` using moles concept.

1. Convert 35 g of `N_2` into the number of mols:

Molar mass of `N_2` = 28.0134 g/mol

Therefore,

number of moles = `frac(35 g)(28.0134 "g/mol") = 1.246 mols approx 1.25 mols`

We have given the balanced chemical equation as:

`N_2 + 3H_2 rightarrow 2NH_3`

From above balanced chemical reaction, we get that:

1 mol of `N_2` produces 2 mols of `NH_3`.

Therefore,

1.25 mols of `N_2` produces 2.5 mols of `NH_3`.

2. Convert 2.5 mols of `NH_3` into g:

Molar mass of `NH_3` = 17.031 g/mol which means

1 mol of `NH_3` = 17.031 g of `NH_3`
2.5 mols of `NH_3` = 42.5775 g of `NH_3` `approx` 42.58 g of `NH_3`

For this first we have to calculate moles of `N_2` from which we can calculate moles of `NH_3`. And from moles of `NH_3`, we can easily calculate its mass.
So let's start:

Moles of `N_2 =``(mass of N_2(grams))/ (molar mass of N_2)`

`= (35grams)/(28grampermol)``= 1.25mols`

Now we have to use balance chemical equation:

`N_2 + 3H_2 to 2NH_3`

As we can see;

`1mol` `N_2` form number of moles of `NH_3 = 2`

`1.25 mols` `N_2` will form number of moles of `NH_3`

`=` `(2molNH_3)/(1molN_2)``xx` `1.25molN_2`

`= 2.5 molsNH_3`

Mass of `NH_3 =` number of moles `xx` molar mass

`= 2.5 xx 17 = 42.5grams`

`Note:`
The coefficients of reactants and products in balance chemical equation represent number of moles. And if there is no coefficient with a molecule then it means that number of mole = 1.