1. Entry Journal 10/31 1.Calculate the number of grams in 5.6 moles of Na 3 PO 4. 2.How many L of O 2 gas are in 7.5 moles of O 2 ?

2. Chapter 9 Stoichiometry: The calculation of chemical quantities in chemical reactions.

3. Stoic. Survival Kit: To be successful in this chapter you will need to: –Balance Chemical Equations –Convert from Moles  molecules Moles  grams Moles  liters (@ STP)

4. Stoic. Study Recommendations Do the homework the night it is assigned. Ask homework questions in class. Go back to your homework and fix problems. Participate whiteboard exercises Practice makes Proficient

5. Look at Balanced Equations C 5 H 12(g) + O 2(g)  CO 2(g) + H 2 O (g) Lets look at: –Atoms (just like balancing the equation) –Molecules/formula units –Moles –mass The only two that are conserved (same on both sides) are atoms and mass!

6. 1C 5 H 12(g) + 8O 2(g)  5CO 2(g) + 6H 2 O (g) Most important relationship: 1 mole of C 5 H 12(g) reacts with 8 moles of O 2(g) to form 5 moles of CO 2(g) and 6 moles of H 2 O (g) We used the balanced equations to come up with conversion factors.

7. Mole-Mole Calculations Chemical equations provide more information than we have had before. We can now relate moles of product to moles of reactant in mathematical equations.

8. 1C 5 H 12(g) + 8O 2(g)  5CO 2(g) + 6H 2 O (g) Mole ratio: A conversion factor derived from the coefficients of a balanced equation. –*** This means that you must ALWAYS check to see if the equation given is balanced… –Used when you want to relate different chemicals Some mole ratios:

9. 1C 5 H 12(g) + 8O 2(g)  5CO 2(g) + 6H 2 O (g) How this shows up in chemistry: Example: How many moles of water are produced when 4 moles of oxygen are reacted? Example: How many moles of pentane are needed to produce 12 moles of CO 2 ?

10. Some Practice: Al (s) + O 2(g)  Al 2 O 3(s) Write the six mole ratios that can be derived from the equation. How many moles of Al are needed to form 3.7 moles of Al 2 O 3 ? ** hint: balance the equation first!!

11. Al (s) + O 2(g)  Al 2 O 3(s) How many moles of O 2 are required to react with 14.8 moles of Al? How many moles of Al 2 O 3 are formed with 0.78 mole O 2 reacts with Al?

12. Remember this? The MOLE Mass (g) Molecules, atoms, formula units Volume (L)

13. Remember this? Let’s add more… The MOLE Mass (g) Molecules, atoms, formula units Volume (L) Relate Chemical A to Chemical B xA  yB

14. Now we can do many more calculations Most common calculation: Mass  Mass It isn’t that much harder, as long as you remember your stuff from chapter 7. Hints: –You ALWAYS need to balance the equation. –Use the mole ratio when you need to change chemicals.

15. 1C 5 H 12(g) + 8O 2(g)  5CO 2(g) + 6H 2 O (g) How this shows up in chemistry: Example: How many moles of water are produced when 20.5 grams of oxygen are reacted? Example: How many grams of oxygen gas are needed to react if 2.8 moles of water are formed?

16. 1C 5 H 12(g) + 8O 2(g)  5CO 2(g) + 6H 2 O (g) Example: How many grams of water will be formed when 552.3 grams of C 5 H 12 are reacted in the presence of oxygen gas?

17. KClO 3  KCl + O 2 How many molecules of O 2 are produced by the decomposition of 6.54 grams of KClO 3 ?

18. CO (g) + O2 (g)  CO 2(g) How many liters of O2 are required to burn 3.86 liters of CO?

19. NO 2 + H 2 O  NO 3 + NO How many grams of NO 2 must react with water to produce 5.00 x 10 23 molecules of NO?

20. CaC 2 + H 2 O  C 2 H 2 + Ca(OH) 2 How many grams of C 2 H 2 are produced by adding water to 5.00 g of CaC 2 ? How many moles of CaC 2 are needed to react completely with 49 g of water?