Page 25 - Pharmaceutical_Analytical_Chemistry_1_Theoretical_Notes_Level_1

Mansoura National University
Pharm D-Clinical Pharmacy Program Level 1 Pharm. Anal. Chem. 1 (PC 101)

Complete the “A” first:
Na + O → Na O
What are the different elements or atoms involved in this reaction? 2 2 2
#R Atom #P
Then complete “R” and “P”.
2× 1 Na 2

Step 2: Go to the first atom that’s not balanced and balance it! 2 O 2

Sodium is not balanced.

What can we do to balance it? Multiply the reactant by 2.
CHANGE THE EQUATION!

2Na + O2 → Na2O2 (This is now balanced!) H2 + O2 → 2 H2O

• Some Equations may require multiple steps to complete. #R Atom #P

Start by creating the RAP table. 2×2 H 2

Oxygen is not balanced! 2 O 2

What can you do balance it?

Multiply the product by 2
• Currently your equation looks like this: H2 + O2 → 2H2O

This is unbalanced. The product is a compound and if you multiply the Oxygen by
2, the number of Hydrogen atoms increases!
• Update the RAP table:

What can we do to balance the number of Hydrogen atoms?

Multiply the reactant by 2.
Your final answer should look like: 2H + O → 2H O
2 2 2
Quiz

Balance the following chemical equations: H2 + O2 → H2O

1. Fe + H S0 → Fe (SO ) + H #R Atom #P
2 4 2 4 3 2
2. CH + O → CO + H O 2 H 2
4 2 2 2
3. SiCl (ℓ) + H O(ℓ) → SiO (s) + HCl(aq) 2 O 2×1
4 2 2

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