Prince Siegfried 1 clutch of corn = 17.5 g (about 130 kernels)

The Mole Purpose – to “count” extremely small objects like atoms, molecules, ions, electrons, etc.,

The Mole – Key Vocabulary Mole – number of carbon-12 atoms needed to give a mass of 12.0 g (there are 6.02 x 1023 particles in a mole) Atomic Mass – the average mass of all isotopes of an atom. (Listed on the Periodic Table.) Molar Mass (aka Formula Mass or Molecular Mass) – total of all atomic masses in a compound. Formula Unit – amount of a compound represented by its formula (ex – One formula unit of NaCl contains one sodium ion and one chloride ion. When dealing with covalent compounds we use the term “molecule” but ionic compounds don’t form molecules, so we use formula units instead.)

The Mole Map Mass City Mole Island Particletown Nitric Acid River Avogadro Memorial Bridge Formula Mass Expressway Mass City Particletown (a.k.a. moleculeburg, atomville, hamlet of ions, formula unit village, etc.,) Mole Island “Gram” Central Station Periodic Table 1 mol = ____g 1 mole = 6.02x1023 particles

Practice… What is the mass of 2.75 moles of carbon dioxide?

Practice… How many silicon atoms are in 0.42 moles of silicon?

Practice… What is the mass of a trillion formula units of magnesium chloride (MgCl2)?

Practice… How many carbon dioxide molecules are there in a 15.861 g sample of carbon dioxide?

Practice… World of Chemistry, p. 189, #20-25. Chemistry: A Modern Course, p. 83, #3-8

The Mole – Key Vocabulary Percent Composition – a list of the percentages, by mass, of the different elements in a compound. Example: The % composition of water is; 11.2 % H, 88.8% O Explanation: The molar mass of water is 18.02 g/mol. Hydrogen makes up 2.02 g/mol and oxygen makes up 16.00 g/mol. 2.02 is 11.2% of the total (18.02) and 16.00 is 88.8% of the total.

The Mole Map Mass City Mole Island Particletown Nitric Acid River Avogadro Memorial Bridge Formula Mass Expressway Mass City Particletown (a.k.a. moleculeburg, atomville, hamlet of ions, formula unit village, etc.,) Mole Island “Gram” Central Station Periodic Table 1 mole = 6.02x1023 particles Part/Whole Mass Path % Composition Industrial Park

Percent Composition… What is the percent composition of aluminum sulfate?

Percent Composition… Which has a higher percentage of nitrogen, ammonium chloride or ammonium sulfide?

Percent Composition… PRACTICE: World of Chemistry, p. 189, #27-30 Chemistry: A Modern Course, pp. 86-87, #17-22

The Mole – Key Vocabulary Empirical Formula – formula which shows the lowest whole number ratio of elements in a compound. Molecular Formula – formula which shows the exact number of each type of atom in a molecule. When the molecular formula is reduced to lowest terms, we get the empirical formula. Ionic compounds don’t form molecules, so we always use empirical formula for these.

The Mole Map Mass City Mole Island Particletown Nitric Acid River Avogadro Memorial Bridge Formula Mass Expressway Mass City Particletown (a.k.a. moleculeburg, atomville, hamlet of ions, formula unit village, etc.,) Mole Island “Gram” Central Station Periodic Table 1 mole = 6.02x1023 particles Part÷Whole Mass Path Lowest Whole # Ratio Empirical Formula % Composition Industrial Park x small whole # Molecular Formula Molecular Mass Empirical Mass =

Empirical Formula… If a 2.00 g sample of copper is heated over a Bunsen burner (exposed to air) and then re- massed, its new mass is 2.25 g. What is the formula of this oxidized product?

Empirical Formula… Analysis of an unknown compound reveals that it is 8.29% aluminum, 32.7% chlorine and 59.0% oxygen. What is the empirical formula of this compound?

Empirical Formula… PRACTICE: World of Chemistry, pp. 189-190, #32-43 Chemistry: A Modern Course, p. 89, #23-26

Molecular Formula… Analysis of an unknown compound reveals that it is 26.7% phosphorous, 12.1% nitrogen and 61.2% chlorine. Further analysis showed the molecular mass of this compound to be about 695 g/mol. What is the molecular formula of this compound?

Molecular Formula… If a half of a mole of a particular compound has a mass of about 46 g and the empirical formula is NO2, what is the molecular formula?

Molecular Formula… A 341.20 g sample of a compound was analyzed and found to contain 2.77 moles and has the empirical formula; C2H3N. What is the molecular formula of this compound?

Molecular Formula… PRACTICE: World of Chemistry, p. 190, #46-50 Chemistry: A Modern Course, p. 90, #27-31

The Mole – Key Vocabulary Hydrate – (or Hydrated Crystal) – a solid substance which has water molecules bound within its crystals in a fixed ratio. Example – CoCl2·6H2O Each formula unit of cobalt (II) chloride has 6 water molecules bound to it. The full name of this hydrated compound is cobalt (II) chloride hexahydrate.

The Mole Map Mass City Mole Island Particletown Nitric Acid River Avogadro Memorial Bridge Formula Mass Expressway Mass City Particletown (a.k.a. moleculeburg, atomville, hamlet of ions, formula unit village, etc.,) Mole Island “Gram” Central Station Periodic Table 1 mole = 6.02x1023 particles Part÷Whole Mass Path Lowest Whole # Ratio Hydrate Peninsula Empirical Formula % Composition Industrial Park x small = Molec. Mass whole # Emp. Mass Molecular Formula

Finding the formula of a hydrate… When a 5.262 g sample of thallium (III) nitrate becomes hydrated it gains 0.728 g of water. What is the formula of the hydrate?

Finding the formula of a hydrate… Help Dr. Hydronius find the formula of a hydrate if 5.56 g of hydrated ytterbium (III) chloride is heated to a constant mass of 4.01 g. (Note: heating a hydrate drives off the water to yield the anhydrous compound.)

Hydrates… PRACTICE: Chemistry: A Modern Course, p. 92, #32-35, and

The Mole – Key Vocabulary Molarity (M) – unit of measure which describes the concentration of a solution. Equation: Molarity = M = Moles of Solute Liters of Solution mol L Types of problems: (1) Given mass of solute and volume of solution, calculate the molarity. (2) Describe how you would make a desired amount of solution of a given concentration.

The Mole Map Mass City Mole Island Particletown Nitric Acid River Molarity M = mol/L Avogadro Memorial Bridge Formula Mass Expressway Mass City Particletown (a.k.a. moleculeburg, atomville, hamlet of ions, formula unit village, etc.,) Mole Island “Gram” Central Station Periodic Table 1 mole = 6.02x1023 particles Part÷Whole Mass Path Lowest Whole # Ratio Hydrate Peninsula Empirical Formula % Composition Industrial Park x small = Molec. Mass whole # Emp. Mass Molecular Formula

Calculating Molarity… Determine the molarity of a solution made by dissolving 1.37 g of lithium hydroxide in enough water to make 250.0 mL of solution.

Solution Preparation… How would you prepare 75.0 mL of a 0.65 M solution of calcium nitrate?

MOLARITY PRACTICE: Orange Text – p. 85, #9-16 Blue Text – p. 500, #21-22

The Mole – Key Vocabulary Dilution – the process of adding solvent to a solution to make it less concentrated. For aqueous solutions we use the phrase “watering it down” to mean the same thing as diluting the solution. This is useful because, rather than purchasing solutions of many different concentrations, you can purchase one solution of high concentration and dilute it to make whatever concentration you need.

DILUTION…the concept… Concentration=mol of solute ÷ L of solution When diluting a solution, which part(s) of the molarity equation change? Which part(s) stay the same? Adding SOLVENT does nothing to change the number of moles of SOLUTE.

Dilution Problems… If 15.8 mL a 2.52 M solution of lithium sulfate is diluted to a total volume of 1.00 L, what is its new concentration?

Dilution Problems… How would you prepare 25.0 cm3 of a 3.75 M solution of hydrochloric acid from a 12.0 M stock solution?

The Mole – Key Vocabulary Molar Volume – one mole of ANY gas at standard temperature and pressure has a volume of 22.4 L. (Standard temperature is 0°C and standard pressure is 760 mm Hg.)

The Mole Map Mass City Mole Island Particletown 22.4 L of gas at STP = 1mol Nitric Acid River Molarity M = mol/L Avogadro Memorial Bridge Formula Mass Expressway Mass City Particletown (a.k.a. moleculeburg, atomville, hamlet of ions, formula unit village, etc.,) Mole Island “Gram” Central Station Periodic Table 1 mole = 6.02x1023 particles Part÷Whole Mass Path Lowest Whole # Ratio Hydrate Peninsula Empirical Formula % Composition Industrial Park x small = Molec. Mass whole # Emp. Mass Molecular Formula

Molar Volume Problems… How many Helium atoms are in a 675 cm3 helium-filled balloon at standard temperature and pressure?

Molar Volume Problems… If 3.52 kg of dry ice (CO2) are place in a balloon, allowed to sublime and reach STP, what volume will the carbon dioxide occupy?