home / study / questions and answers / science / chemistry / balance the following example of a heterogeneous ...

Your question has been answered! Rate it below.

Let us know if you got a helpful answer.
.

Question

Balance the following example of a heterogeneous equilibrium and write its reaction quotient , Qc:

KNO3(s)...........><..........KNO2(s)+ O2(g)

Include the physical states of all reactants and products in your balanced equation.

2KNO3(s) <--> 2KNO2(s) + O2(g)

Qc = (O2)

To balance the equation for this heterogeneous equilibrium, you need to ensure that the number of atoms of each element are the same on both sides of the equation. Here's how you can balance it:

KNO3(s) ↔ KNO2(s) + O2(g)

To balance the equation, follow these steps:

Step 1: Start with the elements that appear in the fewest compounds. In this case, Oxygen (O) is a good choice.

Step 2: Count the number of oxygen atoms on each side of the equation. On the right side, there is only 1 oxygen atom, while on the left side, there are 3 (from the KNO3 compound).

Step 3: To balance the oxygen atoms, you need to add a coefficient in front of the KNO2 compound. Place a coefficient of 2 in front of KNO2:

KNO3(s) ↔ 2 KNO2(s) + O2(g)

Step 4: Next, balance the potassium (K) atoms. On the left side, there is one potassium atom, while on the right side, there are 2 potassium atoms. To balance the potassium atoms, add a coefficient of 2 in front of KNO3:

2 KNO3(s) ↔ 2 KNO2(s) + O2(g)

Now, the equation is balanced with equal numbers of atoms of each element on both sides.

As for the reaction quotient Qc, it is determined by writing an expression using the concentrations of the products and reactants at any given moment. However, since the given equation is in the solid phase (KNO3 and KNO2) and the gas phase (O2), which are not in solution, the concentrations are not applicable. Therefore, the reaction quotient cannot be determined in this case.

To balance the given equation, follow these steps:

Step 1: Write down the unbalanced equation:
KNO3(s) → KNO2(s) + O2(g)

Step 2: Count the number of atoms on each side of the equation:
On the left side: 1 K, 1 N, 3 O
On the right side: 1 K, 1 N, 2 O

Step 3: Balance the atoms in such a way that the number of atoms on both sides is equal. Start with the most complex molecule or the element that appears in only one compound:
In this case, let's start with nitrogen (N):
KNO3(s) → KNO2(s) + O2(g)
There is only 1 nitrogen atom on both sides, so it is already balanced.

Step 4: Next, let's balance the oxygen (O):
KNO3(s) → KNO2(s) + O2(g)
There are 3 oxygen atoms on the left and 2 oxygen atoms on the right. To balance the oxygen, we need to multiply KNO2 by 3 and O2 by 2:
KNO3(s) → 3KNO2(s) + 2O2(g)

Step 5: Lastly, let's balance the potassium (K):
KNO3(s) → 3KNO2(s) + 2O2(g)
There is only 1 potassium atom on both sides, so it is already balanced.

Therefore, the balanced equation for the given heterogeneous equilibrium is:
KNO3(s) → 3KNO2(s) + 2O2(g)

Now, let's write the reaction quotient (Qc):
Qc = [KNO2]³ × [O₂]² / [KNO₃]

Note: The square brackets [] denote the concentration of the respective species involved in the equilibrium.

Remember to provide the concentration values of the reactants and products in order to calculate the Qc value accurately.