Question

1. Ammonia reacts with oxygen according to the equation 4NH3(g)+5O2(g)→4NO(g)+6H2O(g),ΔHrxn=−906 kJ Calculate the heat (in kJ) associated with the complete reaction of 155 g of NH3.

2.

What mass of butane in grams is necessary to produce 1.5×103 kJ of heat? What mass of CO2 is produced? Assume the reaction to be as follows:

C4H10(g)+132O2(g)→4CO2(g)+5H2O(g),ΔHrxn=−2658 kJ

Answer 1

Concepts and reason

The concept used to solve the given problem is the knowledge of balanced equation and stoichiometry.

Stoichiometry is the factor which ensures that the chemical equation is balanced or not. This can be used to determine energy associated to chemical species.

Fundamentals

Stoichiometry is the relative quantities of reactant and products in chemical reactions which relates the total mass of reactant to the products.

(1)

The given reaction when ammonia reacts with oxygen is as follows:

From the balanced equation, it shows that 4 mol of reacts with of to give of and of with the complete reaction.

One mole of contains of gas. So, of contains of gas.

As the heat liberated for the or of gas is .

So, heat liberated for 1 will be as follows:

So, the heat liberated for of gas will be as follows:

(2.1)

The given reaction when butane reacts with oxygen is as follows:

From the given balanced equation, it shows thatof reacts with of to give of and of with the complete reaction.

One mole of contains of gas.

As the heat liberated for the or of gas is .

So, heat liberated for y mol is or .

So, y will be

Now, mass of butane is calculated by formula as follows:

Here M is molar mass of butane and y is number of moles of butane.

Substitute for y and for M.

(2.2)

One mol of butane gas forms of .

So, of butane will produce of . Here x is calculated as follows:

Now, mass of is calculated by formula as follows:

$m=(M)(x) $

Here M is molar mass of butane and x is number of moles of butane.

Substitute for x and for M.

Ans: Part 1

The heat associated with the complete reaction of of is .

Answer 2

Concepts and reason

The concept used to solve the given problem is the knowledge of balanced equation and stoichiometry.

Stoichiometry is the factor which ensures that the chemical equation is balanced or not. This can be used to determine energy associated to chemical species.

Fundamentals

Stoichiometry is the relative quantities of reactant and products in chemical reactions which relates the total mass of reactant to the products.

(1)

The given reaction when ammonia reacts with oxygen is as follows:

From the balanced equation, it shows that 4 mol of reacts with  of  to give  of and  of  with the complete reaction.

One mole of contains  of gas. So,  of contains  of gas.

As the heat liberated for the or  of  gas is .

So, heat liberated for 1 will be as follows:

So, the heat liberated for  of gas will be as follows:

(2.1)

The given reaction when butane reacts with oxygen is as follows:

From the given balanced equation, it shows thatof reacts with of  to give of and of  with the complete reaction.

One mole of contains  of gas.

As the heat liberated for the or  of  gas is .

So, heat liberated for y mol is  or .

So, y will be

Now, mass of butane is calculated by formula as follows:

Here M is molar mass of butane and y is number of moles of butane.

Substitute  for y and  for M.

(2.2)

One mol of butane gas forms  of .

So, of butane will produce  of . Here x is calculated as follows:

Now, mass of  is calculated by formula as follows:

Here M is molar mass of butane and x is number of moles of butane.

Substitute  for x and  for M.

Ans: Part 1

The heat associated with the complete reaction of  of is .