1. Balancing Chemical Equations Rachel DiGiacomo, Kayla Sosa, and Drew Dunne

3. Step One The first step to write correct formulas for the reactants and the products

4. Step Two The second step is to balance the equation This is important to be consistent with the law of conservation of mass *Reminder law of conservations of mass is that atoms are not created or destroyed only rearranged

6. Rules for Balancing Chemical Equations Figure out the correct formula for all reactants and products Write the formula for the reactants on the left On the right of the reactants add a yield sign On the right of your yield sign write the formula to your products

7. Rules Continued Count the number of atoms of each element in the reactants and products *Make it easy on yourself! Count polyatomic ions as a whole if they’re unchanged on both sides Balance the elements one at a time with coefficients *Coefficient is a whole number in front of a chemical formula within a chemical equations *If none assumed to be 1 *Never change subscripts to balance equations

8. Rules Continued Clean it up! Check each atom or polyatomic ion to be sure they’re balanced and simplify by making sure coefficients are in the smallest whole number ratio

9. Try it! We’ll help you C 3 H 8 +O 2 →H 2 O+CO 2 Write this down on a separate piece of paper and try it! For help on how to get started visit the next slide.

11. Did you get it? C 3 H 8 + 5O→ 4H 2 O3CO 2

12. Try Again? H 2 SO 4 +Pb(OH) 4 →Pb(SO 4 ) 2 +HOH 2H 2 SO 4 +Pb(OH) 4 →Pb(SO 4 ) 2 4HOH

13. Every day Applications The burning of natural gas in a gas range Any recipe is a balanced chemical equation. If you are making an omelet and it calls for 2 eggs for each onion, here is the stoichiometry. Now, if you had 6 eggs, you would use 3 onions. And if you had a mole of onions, you would use 2 moles of eggs.

14. Homework Questions __ H2 + __ O2 → __ H2O __H2 + __ N2 → __ NH3