1. Warm-up Give the names for the following: CS2, CrO, CH4 and MgCl2
Give the formulas for the following: Nitric acid, aluminum oxide, copper (III) oxide, and dinitrogen pentoxide
What are the numbers on top and below an element on the periodic table?
Give a definition for the number below an element?

2. Holey Moley!

3. Ewwww….Moles!

4. Moles…in Chemistry?

5. 1 mole = X 1023 particles
(atoms/molecules)

6. 1 mol of
6.022 X 1023 atoms of Mg
1 mol of
6.022 X 1023 atoms of C
1 mol of
6.022 X 1023 atoms of V

7. 1 mol of
6.022 X 1023 molecules of H2O
1 mol of
6.022 X 1023 molecules of CH4 4

8. g/mol
g/mol
Molar Mass
g/mol

9. 1 mol of
g of Carbon
1 mol of
g of Hydrogen

10. Conversion Factors 1 mole of substance = 6.022 X 1023 atoms/molecules
1 mole of substance = molar mass
Molar mass = X 1023 atoms/molecules

11. 12 grams of K2S molecules

12. On Your Own! 1000 grams of calcium is ______ moles of calcium
What is the mass of 3 moles of carbon disulfide?
How many moles of ammonia, NH3, are in 51 grams of NH3
A chemist needs 3 moles of aluminum oxide for an experiment. How many grams of aluminum oxide should she weigh out?
How many molecules of nitric acid are in 5 grams of nitric acid?
You guess that a solution of CrO contains 5.0 X 1020 molecules. How many moles of CrO would be in this solution?

13. Warm-up Give the name or the formula for the following:
K2CO3
Nitric Acid
Hydrochloric Acid
Cu(OH)3
C5H10
1.801 X 1024 atoms Cu = ? g Cu
What is the molar mass for C11H12O11?
Define (in your words) the term “composition.”

14. Chemistry’s Cornucopia

15. Cornucopia
Definition: an abundant supply of good things that are different.

17. Percent Composition
The percent by mass of each element present in a compound.
% composition = 𝑇𝑜𝑡𝑎𝑙 𝑚𝑎𝑠𝑠 𝑜𝑓 𝑒𝑙𝑒𝑚𝑒𝑛𝑡 𝑇𝑜𝑡𝑎𝑙 𝑚𝑎𝑠𝑠 𝑜𝑓 𝑐𝑜𝑚𝑝𝑜𝑢𝑛𝑑 𝑋 100
Mass is determined using the molar mass of an element.

19. Mn(CHO2)2 Mn H O O C C H O O

20. On Your Own!
Find the percent composition for each element of the following compounds:
C12H22O11
Sulfuric Acid
Potassium Permanganate
Chromium (III) Sulfide
Acetic Acid

21. 𝐶𝑜 𝐶𝑙 2 ∙6 𝐻 2 𝑂 Hydrates Cobalt (II) Chloride is hydrated
A compound in which water molecules are chemically bound.
Typically inorganic salts.
In other words, it absorbs water!
Cannot leave hydrates open to air.
𝐶𝑜 𝐶𝑙 2 ∙6 𝐻 2 𝑂
Cobalt (II) Chloride
is hydrated
by 6 molecules of water

22. Percent Composition of Hydrates
We use percent composition to determine the percent of water in a hydrate.
Important in determining unknown hydrates.
What is the percent water in Cobalt (II) Chloride Hexahydrate?

23. On Your Own! Determine the percent water for the following hydrates:
1. 𝐶𝑜 𝐶𝑙 2 ∙6 𝐻 2 𝑂
2. 𝑁𝑎 2 𝐶𝑂 3 ∙10 𝐻 2 𝑂
3.𝑀𝑔 𝑆𝑂 4 ∙7 𝐻 2 𝑂
4.𝐶𝑢 𝑆𝑂 4 ∙5 𝐻 2 𝑂

24. Calculating Empirical and Molecular Formulas
“Step by Step”
Calculating Empirical and Molecular Formulas

25. CH2 1C:2H Empirical Formula “There is 1 carbon for every 2 hydrogens”
The simplest formula of a compound.
The smallest ratio of elements in a compound.
Represents the composition of elements in a compound.
CH2
1C:2H
“There is 1 carbon for every 2 hydrogens”

26. C4H8 4C:8H Molecular Formula
A multiple of the empirical formula.
The actual ratio of elements in a compound.
Represents the structure of elements in a compound.
C4H8
4C:8H
“There are 4 carbons for every 8 hydrogens”

27. Represents composition
Empirical
The simplest formula
Smallest ratio
Represents composition
CH2
1:2 ratio
Molecular
A multiple
Actual ratio
Represents structure
C4H8

28. Empirical Formula Practice

29. “Step by Step”
Change percentage to grams assuming there are 100g of the sample
Divide by the molar mass of each element
Divide the moles of each element by the lowest number of moles of all the elements
Round to whole numbers to find ratios UNLESS there is .5, then multiply each result by 2 for whole number ratios
Write the formula!

30. Problem 1
The percent composition of a compound was found to be 63.5% Silver, 8.2% Nitrogen, and 28.3% oxygen. Determine the compound’s empirical formula.

31. Problem 2
A g sample of an unidentified compound contains 29.84g of Sodium, 67.49g Chromium, and 72.67g Oxygen. What is the compounds empirical formula?

32. Problem 3
A 60.00g sample of an tetraethyl lead, a gasoline additive, contains 38.43g of Lead, 17.83g Carbon, and 3.74g Hydrogen. What is the compounds empirical formula?

33. Warm-up Calculate the following conversions:
88g AgNO3 → molecules of AgNO3
5 mL of HF → molecules of HF (density = 1.15 g/mL)
What is the percent composition of H2SO4?
A 60.00g sample of an tetraethyl lead, a gasoline additive, contains 38.43g of Lead, 17.83g Carbon, and 3.74g Hydrogen. What is the compounds empirical formula?

34. Molecular Formula Practice

35. “Step by Step” Calculate empirical formula
Calculate the mass of the empirical formula
Divide the given mass by the empirical mass, this will give you an element multiplier
Multiply your chemical quantities by the multiplier
Rewrite molecular formula with new chemical values

36. Problem 1
A compound contains 7.19% phosphorus and 92.81% bromine. If this compound has a molecular mass of 431g/mol, what is the molecular formula?

37. Problem 2
Naphthalene is a carbon and hydrogen containing compound often used in moth balls. The empirical formula is C5H4 and its molar mass is g/mol. Find the molecular formula.

38. Investigating Chemical Reactions
Evidence of Chemical Reactions

39. Prime Suspects 𝑟𝑒𝑎𝑐𝑡𝑎𝑛𝑡𝑠→𝑝𝑟𝑜𝑑𝑢𝑐𝑡𝑠 Prime Suspects: Atom and Molecule
Group Affiliation: Chemical Reactions
Group Symbol:
𝑟𝑒𝑎𝑐𝑡𝑎𝑛𝑡𝑠→𝑝𝑟𝑜𝑑𝑢𝑐𝑡𝑠
Crime: Breaking and forming bonds

40. Evidence #1 Precipitate Formation
Highly predictable crime if we analyze solubility rules.
Soluble = dissolves in solution
Insoluble = forms a precipitate (solid)
Surveillance Footage:

41. Evidence #2 Color Change
Intensity of color a result of a reactants being dilute or concentrated.
Surveillance Footage

42. Evidence # 3 Temperature change
Endothermic - Absorbs heat (+∆𝐻), temperature decreases
Exothermic - Releases heat (-∆𝐻), temperature increases
Surveillance Footage:

43. Common Tests for Chemical Reactions
Burning Splint – tests for oxygen, hydrogen, or carbon dioxide
Lime water – tests for carbon dioxide

44. Warm-up
A compound contains 7.19% phosphorus and 92.81% bromine. If this compound has a molecular mass of 431g/mol, what is the molecular formula?
Convert the following:
1.8 x 1024 atoms Br → g Br
What are the three evidences for chemical reactions?
Is ice melting endothermic or exothermic?

45. Types of Reactions

46. Synthesis

47. Decomposition

48. Single Replacement

49. Double Replacement

50. Combustion

51. Identifying Reactions
Identify the following reactions:

52. Balancing Chemical Reactions
Finding Your Balance
Balancing Chemical Reactions

53. Balancing…What does it all mean?

54. Balancing Chemical Reactions
Simple: elements on the reactant side must equal the elements on the product side.
Law of Conservation of Mass
𝑟𝑒𝑎𝑐𝑡𝑎𝑛𝑡𝑠→𝑝𝑟𝑜𝑑𝑢𝑐𝑡𝑠
products
reactants

55. The Law of the Conservation of Mass