Question

The decomposition of ammonia gas (a process that occurs at high temps) is 2KH3(g) --> N2(g) 3H2(g). If a balloon was filled with 3.5L of ammonia gas and all of the gas decomposed, what would be the total volume of gas in the container? Assume the pressure and temp remains constant.

Answer 1

Answer : The total volume of gas in the container will be, 7 liters

Explanation :

The given balanced chemical reaction is,

`2NH_3(g)\rightarrow N_2(g)+3H_2(g)`

From the balanced chemical reaction we conclude that

2 mole of ammonia gas decomposes to give 1 mole of nitrogen gas and 3 moles of hydrogen gas.

According to the Avogadro's Law, the volume of the gas is directly proportional to the number of moles of the gas at constant pressure and temperature.

`V\propto n`

or,

`(V_1)/(V_2)=(n_1)/(n_2)`

where,

`V_1` = initial volume of ammonia gas = 3.5 L

`V_2` = total volume of gas in the container = ?

`n_1` = initial moles of ammonia gas = 2 mole

`n_2` = final moles of all gas (nitrogen + hydrogen) = (1 + 3) = 4 moles

Now put all the given values in the above formula, we get the total volume of gas in the container.

`(3.5L)/(V_2)=(2mole)/(4mole)`

`V_2=7L`

Therefore, the total volume of gas in the container will be, 7 liters

Answer 2

Ammonia gas is
`\text{NH}_3`.

Since the ammonia gas took up 3.5 L at first, using Avogadro's Law, we know that 2 mols of a gas took up 3.5 L at first, but now there are 4 mols of gas in total after the decomposition. Therefore, we can conclude that now the volume in total is 7 L.