How to solve a chemical equations and how to balanced a chemical equation with some examples.Step by step.In each step with some hard equations????? Please

1 Write down your given equation. For this example, you will use:

• C₃H₈ + O₂ --> H₂O + CO₂
• This reaction occurs when propane (C₃H₈) is burned in the presence of oxygen to produce water and carbon dioxide.

2 Write down the number of atoms per each element that you have on each side of the equation. Look at the subscripts next to each atom to find the number of atoms in the equation.

• Left side: 3 carbon, 8 hydrogen and 2 oxygen.
• Right side: 1 carbon, 2 hydrogen and 3 oxygen.

3 Always leave hydrogen and oxygen for last.

4 If you have more than one element left to balance: select the element that appears in only a single molecule of reactants and in only a single molecule of products. This means that you will need to balance the carbon atoms first.

5 Add a coefficient to the single carbon atom on the right of the equation to balance it with the 3 carbon atoms on the left of the equation.

• C₃H₈ + O₂ --> H₂O + 3CO₂
• The coefficient 3 in front of carbon on the right side indicates 3 carbon atoms just as the subscript 3 on the left side indicates 3 carbon atoms.
• In a chemical equation, you can change coefficients, but you must never alter the subscripts.

6Balance the hydrogen atoms next. You have 8 on the left side. So you'll need 8 on the right side.

• C₃H₈ + O₂ --> 4H₂O + 3CO₂
• On the right side, you now added a 4 as the coefficient because the subscript showed that you already had 2 hydrogen atoms.
• When you multiply the coefficient 4 times by the subscript 2, you end up with 8.
• The other 6 atoms of Oxygen come from 3CO₂.(3x2=6 atoms of oxygen+ the other 4=10)

7 Balance the oxygen atoms.

• Because you've added coefficients to the molecules on the right side of the equation, the number of oxygen atoms has changed. You now have 4 oxygen atoms in the water molecules and 6 oxygen atoms in the carbon dioxide molecules. That makes a total of 10 oxygen atoms.
• Add a coefficient of 5 to the oxygen molecule on the left side of the equation. You now have 10 oxygen atoms on each side.
• C₃H₈ + 5O₂ --> 4H₂O + 3CO₂.
• The carbon, hydrogen, and oxygen atoms are balanced. Your equation is complete.

Algebraic Balance

1 Write down the given equation. For this example, we will use:

• PCl₅ + H₂O --> H₃PO₄ + HCl

2 Assign a letter to each substance.

• aPCl₅ + bH₂O --> cH₃PO₄ + dHCl

3 Check the number of each element found on both sides, and set those equal to each other.

• aPCl₅ + bH₂O --> cH₃PO₄ + dHCl
• On the left side, there are 2b atoms of hydrogen (2 for every molecule of H₂O), while on the right side, there are 3c+d atoms of hydrogen (3 for every molecule of H₃PO₄and 1 for every molecule of HCl). Since the number of atoms of phosphorus has to be equal on both sides, 2b must be equal to 3c+d.
• Do this for every element.
  • P: a=c
  • Cl: 5a=d
  • H: 2b=3c+d

4 solve this system of equations to get the numeric value for the coefficients.Since there are more variables than equations, there are multiple solutions. You must find the one where every variable is in its smallest, non-fractional form.

• To quickly do this, take on variable and assign a value to it. Let's take b=1. Then start solving the system of equations to get the following values:
  • a=1/4
  • b=1
  • c=1/4
  • d= 5/4
• Multiply everything by 4 to get the smallest, non-fractional solution.
  • a=1
  • b=4
  • c=1
  • d= 5