DAY 1: HOW MUCH SODIUM ? COUNTING NAILS BY THE POUND COUNTING ATOMS BY THE GRAM Chapter six

Why Is Knowledge of Composition Important? Tro's "Introductory Chemistry", Chapter 6 2 Some Applications:  The amount of sodium in sodium chloride for diet.  The amount of iron in iron ore for steel production.  The amount of hydrogen in water for hydrogen fuel.  The amount of chlorine in freon to estimate ozone depletion.

Counting Nails by the Pound Tro's "Introductory Chemistry", Chapter 6 3 A hardware store customer buys 2.60 pounds of nails. A dozen nails has a mass of pounds. How many nails did the customer buy? 1 dozen nails = lbs. 12 nails = 1 dozen nails Solution map:

Counting Nails by the Pound, Continued Tro's "Introductory Chemistry", Chapter 6 4 The customer bought 2.60 lbs of nails and received 208 nails. He counted the nails by weighing them!

Counting Atoms by Moles Tro's "Introductory Chemistry", Chapter 6 5 If we can find the mass of a particular number of atoms, we can convert the mass of an element sample to the number of atoms in the sample. The conversion factor we will use is the MOLE  1 mole = x things.  Like 1 dozen = 12 things.  Avogadro’s number.

Moles- as a conversion factor Tro's "Introductory Chemistry", Chapter 6 6 Mole = Number of things equal to the number of atoms in 12 g of C-12.  1 atom of C-12 weighs exactly 12 amu.  1 mole of C-12 weighs exactly 12 g. In 12 g of C-12 there are x10 23 C-12 atoms.

Conversions When converting between moles and number of atoms  Use the conversion factor:  1 mole = 6.02 x10 23 atoms Practice: A silver ring contains 1.1 x silver atoms. How many moles of silver are in the ring?

Conversions continued When converting from grams to moles of an element  Use the conversion factor:  Molar mass (atomic mass in grams) = 1 mole Practice: Calculate the number of moles of sulfur in 57.8 g of sulfur.

Conversions, continued When converting between grams and number of atoms  Use two conversion factors  molar mass= 1 mole and then 1 mole = x10 23 atoms Practice: How many aluminum atoms are in an aluminum can with a mass of 16.2 g?

Tro's "Introductory Chemistry", Chapter 6 10 g Almol Alatoms Al Information: Given:16.2 g Al Find:? atoms Al Conversion Factors: 1 mol Al = g 1 mol = x Example: How many aluminum atoms are in an aluminum can with a mass of 16.2 g? SOLUTION:

COUNTING MOLECULES BY THE GRAM CHEMICAL FORMULAS AS CONVERSION FACTORS Day 2:

Tro's "Introductory Chemistry", Chapter 6 12 Molar Mass of Compounds The relative weights of molecules can be calculated from atomic weights. Formula mass = 1 molecule of H 2 O = 2(1.01 amu H) amu O = amu. Since 1 mole of H 2 O contains 2 moles of H and 1 mole of O. Molar mass = 1 mole H 2 O = 2(1.01 g H) g O = g.

Conversions When converting from grams to moles of a compound  Use the conversion factor:  Formula mass (in grams) = 1 mole Practice: Calculate the number of moles of Hydrogen in 57.8 g of water.

Conversions, continued When converting between grams and number of molecules  Use two conversion factors  formula mass= 1 mole and then 1 mole = x10 23 molecules Practice: How many carbon dioxide molecules are in 45.3g of dry ice (carbon dioxide)?

Tro's "Introductory Chemistry", Chapter 6 15 Chemical Formulas as Conversion Factors 1 spider  8 legs. 1 chair  4 legs. 1 H 2 O molecule  2 H atoms  1 O atom.

Tro's "Introductory Chemistry", Chapter 6 16 Counting Parts We can use the total number to determine the number of each part:  When all the desks in the room have 4 legs, if there are 30 desks in the room, there will be 120 legs (4 x 30).  Since every H 2 O molecule has 2 H atoms, in 100 H 2 O molecules, there are 200 H atoms.  In 1 mole of H 2 O molecules, there are 2 moles of H atoms.

Tro's "Introductory Chemistry", Chapter 6 17 Mole Relationships in Chemical Formulas Since we count atoms and molecules in mole units, we can find the number of moles of a constituent element if we know the number of moles of the compound. Moles of compoundMoles of constituents 1 mol NaCl1 mol Na, 1 mol Cl 1 mol H 2 O2 mol H, 1 mol O 1 mol CaCO 3 1 mol Ca, 1 mol C, 3 mol O 1 mol C 6 H 12 O 6 6 mol C, 12 mol H, 6 mol O

Converting from moles of compound to moles of (constituent) part Calculate the Moles of Oxygen in 1.7 Moles of CaCO 3  1.7 moles of CaCO 3 x 3 mole O = 5.1 mol O  1 mole CaCO 3

Tro's "Introductory Chemistry", Chapter 6 19 Carvone (C 10 H 14 O) is the main component in spearmint oil. It has a pleasant odor and mint flavor. It is often added to chewing gum, liqueurs, soaps, and perfumes. Find the mass of carbon in 55.4 g of carvone. Converting from mass of compound to mass of part

QUIZ Day 3:

Day 4:

BAGGIE LAB & WRITE UP Day 5:

Day 6

EMPIRICAL LAB Day 7

Day 8:Lab write up Day 9: Review Day 10: Chapter 5/6 Test