1. Chapter 5 Chemical Reactions
When you hear the term chemical reaction, what do you think of? In general, you take one or more chemicals and do something to it to make something new.

2. The Mole
A critical part of every chemical reaction is this little guy. A cute little mole. Why is this little guy so important? He or she, I don’t know much about moles to tell the difference, but this mole is the way in which chemists determine how much of each compound to measure out. Now they do not actually use real moles to do all the work for them, but the unit “the mole” is a keep track of the molecules we are reacting.

3. 2 pairs of kings = 2 x 2 kings = 4 kings 2 dozen eggs = 24 eggs
1 pair of kings = 2 kings
1 dozen eggs = 12 eggs
To clarify lets look at how we count things. When we have 12 of something, in this case 12 eggs, we can instead call that a dozen eggs. The term dozen represents 12 of soemthing, so a dozen eggs represents how many eggs? 12. In the same way, if we have 2 of something, like in this case two kings, we can say we have a pair of kings. A pair represents two kings. If we have 2 pairs of kings we have 2 x 2 kings which is 4 kings. If you play poker this is where you go all in.
2 pairs of kings = 2 x 2 kings = 4 kings
2 dozen eggs = 24 eggs

4. The Mole 1 mole = 6.022 x 1023 things Avogadro’s number
The number of carbon atoms in 12g of C-12
Abbreviation: “mol”
This leads us back to the concept of the mole. 1 mole represents a certain number of something. How much? x 1023 of something. That is a really big number. The purpose of a mole is to keep track of something when there is a lot of something, for example atoms. 12grams of carbon ( the 12C isotope) of carbon contains X 1023 atoms of carbon, which is one mole of carbon atoms.
How much does this weigh?

5. 1 mole C atoms = 6.022 x 1023 Carbon atoms
6.022 x 1023 Carbon atoms = 1 mole of carbon atoms
1 mole bicycles = x 1023 bicycles
6.022 x 1023 bicycles = 1 mole of bicycles
1 mole of anything = x 1023 items of anything
6.022 x 1023 items of anything = 1 mole of anything

6. Here are some example of how much a mol of each of the elements looks like. For example in this first container with Copper in it, this contains one mole of copper. How many atoms of copper is that? 6.022x It is the same situation for each sample. In every case, the term “mole” is used to represent a certain number of atoms in a given sample.
Cu, Al, Pb, S, Mg, Cr

7. Molar Mass The mass, in grams, of one mole of any element or compound
Abbreviated with capital, italicized M or MW
Unit = grams/mole = g/mol
Also called Formula Mass and Formula Weight
Gives us a way to go from grams to moles
Now with the concept of the mole in our minds. We can talk about molar mass. This is the mass in grams of one mole of any element or compound. This term can be abbreviated with an italicized M or either the letters MW. The units of Molar mass are grams per mole. Grams divided by the moles. Since the molar mass represents a relationship between grams and moles of something, we can use it to solve various equations. If you have the grams of something you can use Molar mass as the tool to get to moles. Or if you have the moles of something, you can use molar mass as the tool to get to grams. As shown in the example schemes, grams divided the molar mass gives the amount of moles, or moles mulitplied by the molar mass gives the amount in grams.

8. Molar Mass Molar mass = Formula weight = Formula mass
When you talk about molecules
Molar mass = Molecular weight = MW
Generalized formula
Molecular weight = grams/ moles
MW = g/mol
Use periodic table to figure out Molar mass for each atom.
Molar mass has various names that essentially mean the same thing. You can also call it Formula weight or Formula mass. If you are considering molecules you can also say molecular weight and represent it with the letter MW. Shown also is the generalized formula where Molar mass = grams/moles

9. Problems
You need mol Cu for an experiment, how many grams should you use? How many atoms of Cu is this?
You have g Hg. How many moles are present? If Hg has a density of g/mL, what volume do you have?
Lets use this to solve some problems.

10. Write the molecular formula or formula unit for the compounds above.
Cl-
Na+
Cl-
Na+
Cl-
Na+
Cl-
Na+
Write the molecular formula or formula unit for the compounds above.
What are the molecular and formula weights for the compounds above?

11. What is the mass of 1. 34 mole of the first compound
What is the mass of 1.34 mole of the first compound? What is the mass of carbon in this sample?
How many moles of Sodium Chloride are present in 9.29 g? How many moles of sodium are present in the sample?
How many oxygen atoms are there in 5.62g of Carbon Dioxide?

12. Your nurse gives you 10. 0g morphine, C17H19NO3 , for pain
Your nurse gives you 10.0g morphine, C17H19NO3 , for pain. How many moles is this? How many grams of oxygen are present in this dose of analgesic?

13. Chemical Equations H2 (g) + Cl2(g)  2 HCl (g) Reactants Product(s)
Coefficient
Physical State
Subscript
H2 (g) + Cl2(g)  2 HCl (g)
Reactants
Product(s)

14. Law of Conservation of Matter/Mass
Matter is neither created, nor destroyed, but is merely rearranged
The mass of the reactants must equal the mass of the products
H2 (g) + Cl2(g)  2 HCl (g)

15. Balancing Chemical Equations
Zn(s) + HCl(aq)  H2(g) + ZnCl2(aq)
Write the unbalanced equation
Balance the atoms of one element
Choose another element and balance it
Continue until all elements have the same number of atoms on both sides of the equation
Check yourself

16. Problems __ N2(g) + __ H2(g)  __ NH3(g)
__ Fe(s) + __ Cl2(g)  __ FeCl3(s)
__NH3(g) + __O2(g)  __NO(g) + __H2O(g)
__C5H12(l) + __O2(g)  __CO2(g) + __H2O(g)

17. General Reactions
Combination rxns: 2 or more substances react to form a single product
2 H2 + O2  2 H2O

18. Decomposition rxns: single substance decomposes into 2 or more products
opposite of combination rxns
2 H2O  2 H2 + O2

20. Single replacement/displacement: one element reacts with a compound to form a new compound and release a new element
2 Na + 2 H2O  2 NaOH + H2

21. Exchange or Double replacement/displacement: an interchange of partners between two compounds
Pb(NO3)2(aq) + K2CrO4(aq)  PbCrO4(s) + 2 KNO3(aq)

22. Combustion rxns: the burning of a compound, usually a hydrocarbon, in oxygen to form heat, carbon dioxide and water

23. Problems
Balance the following equations and identify the type of reaction present.
__C3H8(g) + __O2(g)  __CO2(g) + __H2O(g)
__BaCl2(aq) + __Na2SO4(aq)  __BaSO4(s) + __NaCl(aq)
__Fe(s) + __H2O(l)  __Fe3O4(s) + __H2(g)
__Pt(s) + __F2(g)  __PtF4(l)
__H3BO3(s)  __B2O3(s) + __H2O(l)
__C4H10(g) + __O2(g)  __CO2(g) + __H2O(g)

24. Preview of doom (aka stoichiometry problems)
1) If you have 10.0g C4H10 (butane), how many grams of water can you make upon combustion?

25. Stoichiometry
Calculations of the relative quantities of reactants and products in chemical reactions
How much of something do you need to make something else
You learned how to use moles
You learned about chemical reactions and balancing equations.
Now it all comes together!!!

26. Stoichiometric guidelines
Make sure you have a balanced chemical equation
Use the balanced equations to make molar ratios between reactants and products or reactants and reactants or products and products. Use moles of something to get to moles of something else
Use what you are given to get where you are going

27. Stoichiometric Flow Chart
Molar ratios: Using coefficients of balanced equation
Moles of A
Moles of B
MW = g/mol
MW = g/mol
grams of A
grams of B
D = g/mL
D = g/mL
Volume of B
Volume of A

28. Stoichiometry Problems
If you have 10.0g C4H10 (butane), how many grams of water can you make upon combustion?
How much O2 do you need in problem 1 if you’d like to produce 7.39g CO2?
How much CO2 is produced upon combustion of 4.3g of propane (C3H8)?

29. __C6H12O6(s) + __O2(g)  __CO2(g) + __H2O(l)
Using the equation below, calculate the amount of glucose you started with if you produced 12.76g CO2?
How much glucose was consumed in order to produce mL of H2O?
__C6H12O6(s) + __O2(g)  __CO2(g) + __H2O(l)

30. Jim Bob got a job at a chair factory
Jim Bob got a job at a chair factory. His boss tells him that he’s going to lunch and when he comes back, Jim Bob better have 5 chairs made or he’s fired. JB gets to work. He counts 32 arms, 18 legs, 4 backs, and 2 seats. Will JB get fired?

31. Limiting Reagent
Limiting Reagent/Reactant/Factor: the reactant/factor that determines the amount of product formed
Other reactants are “in excess”
Cheaper reactants are usually in excess

32. Problems
You have 10.0 moles H2 and 1.00 mol O2. How much H2O can you make?
You combust 10.2 mol propane in 7.80 mol O2. How much CO2 can you produce?

33. If 2. 3 mol carbon disulfide reacts with 5
If 2.3 mol carbon disulfide reacts with 5.4 mol oxygen to form carbon dioxide and sulfur dioxide, what mass of sulfur dioxide is formed?
5.50 g silicon dioxide reacts with 4.71g Carbon to from silicon carbide and carbon monoxide. What mass of carbon monoxide is formed?

34. Jim Bob got a job at a chair factory
Jim Bob got a job at a chair factory. His boss tells him that he’s going to lunch and when he comes back, Jim Bob better have 5 chairs made or he’s fired. Jim Bob gets to work. He counts 32 arms, 18 legs, 4 backs, and 2 seats. Will Jim Bob get fired?
Jim Bob 

35. 2 arms + 4 legs + 1 back + 1 seat  1 chair
32 arms, 18 legs, 4 backs, 2 seats

37. Percent Yield
Theoretical Yield: the maximum possible quantity of product
100% yield
Actual/Experimental Yield: quantity of product actually obtained
Percent Yield: efficiency of reaction
PY = (actual yield/theoretical yield) x 100

38. Problems
From the previous question, the theoretical yield of CO is 5.13 g. If you obtained 4.32g CO, what was your % yield?
You react 4.41 mol carbon monoxide with 8.39 mol hydrogen gas to get 122g methanol. What is your percent yield?

39. Chapter 5 Review Mole – 6.022x 1023 of something
Molar Mass – M = grams/mole of an element or compound. Know how to find out the grams, moles or molar mass of a element or compound depending on whats given.
Chemical equations – know how to identify components and how to balance an equation
Combination, decomposition, single and double replacement, and combustion reactions. Know which one is which.
Limiting reagent- you can only obtain product based on which compound you have the least of
Percent yield – How much product did you get compared to what you should of got