What is Chemical Equation?
A chemical equation is a symbolic representation of a chemical reaction. It shows the reactants, products, and their chemical formulas. Chemical equations help us understand and visualize chemical reactions, as well as predict the products of a reaction.
In a chemical equation, the reactants are on the left, and the products are on the right. An arrow is used to separate the reactants and products, and it indicates the direction of the reaction. When the arrow points to the right in a chemical equation, it means that the reaction is moving forward. When the arrow points to the left, it means the reaction is moving backward.
Chemical equations also indicate the physical state of the entities involved in the reaction. Solid, liquid, gas, and aqueous states are usually described by the letters (s), (l), (g), and (aq), respectively (dissolved in water).
Here's an example chemical equation:
This equation represents the reaction between hydrogen gas and oxygen gas to produce liquid water. The number in front of each chemical formula indicates the stoichiometric coefficient, which represents the relative number of molecules or moles of each substance involved in the reaction.
Why must Chemical Equations be balanced?
A chemical reaction undergoes a lot of changes. A chemical reaction is initiated so that we can get something. Chemical equations must be balanced to get the desired output from the chemical reaction.
Chemistry equations are crucial for obtaining the right product from the chemical reaction. That's why complex equations must be balanced.
How to balance Complex Chemical Equations?
Balancing chemical equations is a crucial concept in chemistry, necessary for reaction analysis, lab work, and stoichiometry. In this article, we will discuss the easiest ways to balance complex chemical equations that comprise more than five elements.
Previously, we have covered methods for balancing general chemical equations and balancing redox reactions in basic solutions. However, complex equations require additional techniques and strategies.
By following some simple steps, you can balance complex equations successfully. First, identify the reactants and products and determine the number of atoms of each element. Next, use coefficients to balance the equation by adjusting the number of atoms on each side.
Why do general equation balancing methods not work well with complex chemical equations?
There are two main methods of balancing difficult chemical equations. The first one is the trial and error method, while the second one is the atom counts.
The first method of balancing chemical equations is taught in school. This method of balancing chemical equations is simple and easy to understand.
Balancing complex chemical equations get prolonged if we use other methods. The trial and error or atom counts method makes the procedure quite lengthy.
The trial and error and atom count methods are suitable for equations having 2-3 atoms. Since both are general methods, it will take our time to complete the process. It takes around 30 minutes to balance a chemical equation having 5-7 elements.
Balancing complex chemical equations by algebra
The algebraic method is an efficient and precise way to balance complex chemical equations. Although the combination of chemical equations and algebra may sound intimidating, it is not as difficult as it seems.
In fact, balancing chemical equations using algebraic methods is easier than solving simultaneous equations in A-level math. With the algebraic method, you can solve unbalanced equations that are difficult to balance using inspection or the atom count method.
This algebraic method is further divided into two main types:
- General algebraic method
- Simplified algebraic method
How to balance Complex Equations using General Algebraic Method
Balancing complex chemical equations using algebra can be achieved through a general strategy that involves four steps:
- Add a coefficient letter to each compound present in the equation.
- Apply algebraic expressions for each element to equalize the number of atoms on both sides of the equation.
- Discard the unknown coefficient letter by substituting it with a numerical value.
- Add the coefficient values to get the final balanced equation.
While these steps may seem confusing at first, let's walk through an example to demonstrate the process:
Step 1: Add Coefficient
First of all, we will add the letter coefficient in front of each compound as follows
Step2: Apply Algebraic Rules
After this, we will apply the algebraic rules to make the equations perfect according to the law of mass conservation.
We will start by writing rules for K since it is the first element from L.H.S in the process of equation balancer. After this, we will use the same method to write different algebraic rules for each entity, such as
K: a = d
Mn: a = c
O: a = f
H: b = f
Cl: b = 2c + d + 2e
You could be confused about the last rule so let us explain this to you. According to the law of mass construction, the number of Cl atoms would be the same on both sides.
According to the formula [Cl: b = 2c + d + 2e], the reactant side contains b number of Cl atoms.
While cMnCl2 contains two chlorine atoms and its coefficient letter is C. We wrote the rule for cMnCl2 as 2c.
KCl would have a d number of chlorine atoms. Thus, on adding up the coefficient values for c, d, and e at R.H.S, we will get the value of b at L H.S.
Step 3: Discard Unknown Coefficient
In the next step, we will discard the unknown coefficients and simplify the rules by adding common substitutes for each element.
Let's start with the chlorine atoms and substitute the rules for Mn and K to remove c and d from equations such as
b = 2c + d + 2e converted to b = 2a + a + 2e
On further simplifying the equation, it would become
b = 3a + 2e
Now, time to substitute the rules for H to eliminate b
2f = 3a + 2e
And lastly, substitute the rule for oxygen atom to add eliminate f
2(4a) = 3a + 2e
8a = 3a + 2e
5a = 2e : a = 2 and e=5
We have found the coefficient values for a and e. Use these values and the fact a = c = d = 2 into the rules for O and Cl to find the coefficient values for b and f
b = 2c + d + 2e
b = 3a + 2e
b = 3 . 2 + 2 . 5
b = 16
Now derive the value of f as follows
4a = f
4 . 2 = f = 8
Step# 4: Add Coefficient Value
Now add all these coefficient values to the equation (2) to get your final balanced equation
2KMnO4 + 16HCl → 2MnCl4=2 + 2KCl + 5Cl2 + 8H2O
How to balance Complex Equations using Simplified Algebraic Method
If you have understood the general algebraic method thoroughly, you must think that if a = c = d, what is the need to add them in the first place?
Why not write the whole thing simplified from the very first point? That's precisely the purpose of using a simplified algebraic method.
To understand the exact procedure of solving unbalanced equations by the simplified algebraic method, There are a lot of complex chemical reaction examples. One of complex chemical reaction balancer example is given below:
Step 1: Identify atoms
The first step in balancing a chemical equation is to identify the atoms present on both sides of the equation. In our example, we have:
LHS: K, Mn, O, H, Cl
RHS: Mn, Cl, K, Cl, O, H
We can see that the Mn and K atoms are already balanced, so we will use a similar coefficient letter for them. Let's assume 'a' for the coefficient letter.
Next, we need to balance the unbalanced atoms, which are O, H, and Cl.
Step 2: Balance the unbalanced atoms
We can see that there is one oxygen atom on the RHS in the form of a water molecule (H2O). On the LHS, we have four oxygen atoms in the KMnO4 molecule. To balance the oxygen atoms, we will write the coefficient for H2O as 4a.
Next, we need to balance the hydrogen atoms, which are present in the HCl and H2O molecules. Since there are four water molecules on the RHS, we need to balance the hydrogen atoms by adding 8aHCl on the LHS.
Finally, we need to balance the chlorine atoms, which are present in the Cl2 molecule. Since there is no Cl2 molecule on the LHS, we will write the coefficient for Cl2 as 'b.'
Step 3: Write algebraic equations
Now, we will write the algebraic equations for each coefficient value to balance the equation.
For oxygen atoms: 4a = 4
a = 1
For hydrogen atoms: 8a = 2a + 2b + 16
6a = 2b + 16
b = 5
For chlorine atoms: a = a + b + 2
1 = 1 + 5 + 2
The equation is now balanced, and the final balanced equation is:
What's the easiest way to balance a chemical equation?
The easiest way to balance a chemical equation is to list the number of names and elements involved first. If we have:
On the right side of the equation, we have one iron and two chlorine. On the left side, we have one iron and three chlorine. To balance the equation, we need to make the number of atoms of each element equal on both sides.
We start by dividing both sides by the smallest count, which is 2. This gives us:
Fe + (3/2)Cl2 → (2/3)FeCl3
Next, we need to multiply each coefficient by 2 to get rid of the fraction:
2Fe + 3Cl2 → (4/3)FeCl3
To make the coefficients whole numbers, we multiply both sides by 3:
6Fe + 9Cl2 → 4FeCl3
Finally, we check if the coefficients are whole numbers and make any necessary adjustments. In this case, we have two irons on the left side and four irons on the right side. To balance this, we add a coefficient of 2 in front of Fe on the left side:
2Fe + 9Cl2 → 4FeCl3
And there you have it! A balanced chemical equation in just a few simple steps.
Frequently asked question
What is a chemical equation?
A chemical equation is a symbolic representation of a chemical reaction using chemical formulas and symbols.
Why must chemical equations be balanced?
Chemical equations must be balanced to satisfy the law of conservation of mass, which states that mass cannot be created or destroyed in a chemical reaction.
How can complex chemical equations be balanced?
Complex chemical equations can be balanced by using a trial-and-error method or the algebraic method.
Why do general equation balancing methods not work well with complex chemical equations?
General equation balancing methods may not work well with complex chemical equations because they often involve multiple steps and complex reactions.
What is the algebraic method of balancing complex chemical equations?
The algebraic method of balancing complex chemical equations involves using algebraic equations to represent the reactants and products of a chemical reaction and solving for the coefficients.
How is the general algebraic method used to balance chemical equations?
The general algebraic method is used to balance chemical equations by following a systematic approach that involves assigning variables to each compound, writing the algebraic equations, and solving for the coefficients.
What are the steps involved in balancing chemical equations using the general algebraic method?
The steps involved in balancing chemical equations using the general algebraic method are:
- a) Write the chemical equation and assign variables to each compound.
- b) Write the algebraic equation by using the variables and balancing the atoms on both sides of the equation.
- c) Solve the algebraic equations by using a system of linear equations.
- d) Check the balanced equation to ensure that the law of conservation of mass is satisfied.