1. Balancing Equations tutorial This tutorial will take you through steps necessary to balance chemical equations.

2. Law of the Conservation of Mass The law of conservation of mass states that the mass of the starting material equals the mass of all products at the end of the reaction. In chemical terms, mass is equivalent to the elements involved.

3. Consequences If the Law of conservation of mass was not correct: Imagine eating a sandwich---- a chemical reaction that occurs in your mouth----if the law of conservation of mass did not exist, your food could disappear (or increase in size) from time to time.

4. Steps to solve a balancing equations problem Organize your information Examine the formulae in the problem Check rows and columns to keep track of the problems.

5. Sample problem __ KCl + __ Fe 2 O 3 => __ K 2 O + __ FeCl 3

6. Step 1: Setup The double line is like an equal sign. __ KCl + __ Fe 2 O 3 => __ K 2 O + __ FeCl 3

7. Step 2: Initial inventory List elements (or ions). __ KCl + __ Fe 2 O 3 => __ K 2 O + __ FeCl 3 K Cl Fe O

8. Step 3: Inventory formulas __ KCl + __ Fe 2 O 3 => __ K 2 O + __ FeCl 3 K __ x 1 __ x 2 Cl __ x 1__ x 3 Fe __ x 2__ x 1 O __ x 3__ x 1

9. Step 4: Check set-up __ KCl + __ Fe 2 O 3 => __ K 2 O + __ FeCl 3 K __ x 1 __ x 2 Cl __ x 1__ x 3 Fe __ x 2__ x 1 O __ x 3__ x 1 All numbers match the formulas.

10. Step 5: Filling in the table Here are the basic rules and hints: –For each row, the left side of the double line must equal the right side of the double line. –For each column, Each underlined number MUST be the same. –Begin in a row where the numbers are not the same. –When you fill in row, continue from the numbers that you filled in. DO NOT JUMP AROUND THE TABLE.

11. Start with row of Cl Least common multiple of 1 and 3 is 3. __ KCl + __ Fe 2 O 3 => __ K 2 O + __ FeCl 3 K __ x 1 __ x 2 Cl _3 x 1 1 x 3 Fe __ x 2__ x 1 O __ x 3__ x 1

12. Since we see a 3 underlined in the first column, we can enter a three in the row above __ KCl + __ Fe 2 O 3 => __ K 2 O + __ FeCl 3 K _3 x 1 __ x 2 Cl _3 x 1 1 x 3 Fe __ x 2__ x 1 O __ x 3__ x 1

13. We have a problem here. The number that would fit in the Potassium row would be 1.5, but all numbers must be whole numbers so multiple by 2. __ KCl + __ Fe 2 O 3 => __ K 2 O + __ FeCl 3 K _3 x 1 __ x 2 Cl _3 x 1 1 x 3 Fe __ x 2__ x 1 O __ x 3__ x 1

14. We have a problem here. The number that would fit in the Potassium row would be 1.5, but all numbers must be whole numbers so multiple by 2. __ KCl + __ Fe 2 O 3 => __ K 2 O + __ FeCl 3 K _6 x 1 __ x 2 Cl _6 x 1 2 x 3 Fe __ x 2__ x 1 O __ x 3__ x 1

15. Continue on with the potassium row __ KCl + __ Fe 2 O 3 => __ K 2 O + __ FeCl 3 K _6 x 1 _3 x 2 Cl _6 x 1 2 x 3 Fe __ x 2__ x 1 O __ x 3__ x 1

16. Now the Potassium oxide column __ KCl + __ Fe 2 O 3 => __ K 2 O + __ FeCl 3 K _6 x 1 _3 x 2 Cl _6 x 1 2 x 3 Fe __ x 2__ x 1 O __ x 3_3 x 1

17. Now the oxygen row __ KCl + __ Fe 2 O 3 => __ K 2 O + __ FeCl 3 K _6 x 1 _3 x 2 Cl _6 x 1 2 x 3 Fe __ x 2__ x 1 O _1 x 3_3 x 1

18. Now the Iron (III) oxide column __ KCl + __ Fe 2 O 3 => __ K 2 O + __ FeCl 3 K _6 x 1 _3 x 2 Cl _6 x 1 2 x 3 Fe _1 x 2__ x 1 O _1 x 3_3 x 1

19. Now the Iron row. __ KCl + __ Fe 2 O 3 => __ K 2 O + __ FeCl 3 K _6 x 1 _3 x 2 Cl _6 x 1 2 x 3 Fe _1 x 2 2 x 1 O _1 x 3_3 x 1

20. The underlined numbers in the Iron (III) chloride column match. This is a good sign. __ KCl + __ Fe 2 O 3 => __ K 2 O + __ FeCl 3 K _6 x 1 _3 x 2 Cl _6 x 1 2 x 3 Fe _1 x 2 2 x 1 O _1 x 3_3 x 1

21. Check to see if each row equals out on the left and right sides of the double lines. __ KCl + __ Fe 2 O 3 => __ K 2 O + __ FeCl 3 K _6 x 1 _3 x 2 Cl _6 x 1 2 x 3 Fe _1 x 2 2 x 1 O _1 x 3_3 x 1

22. Check to see if each underlined number in each column is the same. __ KCl + __ Fe 2 O 3 => __ K 2 O + __ FeCl 3 K _6 x 1 _3 x 2 Cl _6 x 1 2 x 3 Fe _1 x 2 2 x 1 O _1 x 3_3 x 1

23. The numbers all check, so we can fill in the coefficients in the equation. 6 KCl + 1 Fe 2 O 3 => 3 K 2 O + 2 FeCl 3 K _6 x 1 _3 x 2 Cl _6 x 1 2 x 3 Fe _1 x 2 2 x 1 O _1 x 3_3 x 1

24. You are done. The answer is 6 KCl + 1 Fe 2 O 3 => 3 K 2 O + 2 FeCl 3