ATB Question: What is the base unit used to measure the amount of substance? MOLE PROJECT DUE TODAY! VOCABULARY QUIZ TODAY!

CHAPTER 10 THE MOLE

CHEMICAL MEASUREMENTS MOLE: The # of atoms of an element equal to the # of atoms in exactly 12.0 grams of carbon- 12 –always 6.02 x atoms Establishes a Relationship between:amu’s (atomic mass units) and grams (a measurable quantity) Sometimes referred to as: Avogadro’s Number (N) –In honor of Amadeo Avogadro, an Italian chemist and physicist

Familiar Counting Units 1 dozen eggs = ____ eggs 1 ream of paper = _____ sheets of paper 1 mole of carbon = ____________________________________ atoms of carbon

What’s a mole equal to? Element’s are made of:______________ –So when the substance is an element 1 mole = 6.02 x __________________ atoms

Molecular compounds are made of _____________ –So when the substance is a molecular compound or diatomic molecule 1 mole = 6.02 x __________________ What’s a mole equal to? molecules

Ionic compounds are made of _______________ –So when the substance is an ionic compound 1 mole = 6.02 x _________________ What’s a mole equal to? Formula units

The mass in grams of one mole of an element is numerically equal to the atomic mass of that element.

Formula Mass: The sum of the masses of all the atoms in a compound. –Units: amu (atomic mass units) Molar Mass: The mass in grams of 1 mole of substance –Units: grams/mole Molar Mass = Atomic Mass or Formula Mass –b/c the mass of 1 mole of an element is equal to the atomic mass of that element

EXAMPLES Find the formula mass of water. Find the formula mass of acetic acid, HC 2 H 3 O 2. Find the formula mass of baking soda, NaHCO 3

d)C 6 H 12 O 6 : grams/mole e)CO: grams/mole f)Mg(OH) 2 : grams/mole g)HCl: grams/mole EXAMPLES-ANSWERS

ATB QUESTION: What element do moles love to study in chemistry?

MOLAR CONVERSIONS The mole is a measurement for mass, # of particles and volume –Therefore, the mole is a central unit in chemistry for converting the amount of one substance from one type of measurement to another

MOLE  MASS 1 mole = molar mass (grams) The conversion factors are: 1 moleormolar mass molar mass1 mole

MOLE  PARTICLES 1 mole = 6.02 X atoms, molecules or formula units The conversion factors are: 1 mole 6.02 x atoms molecules or fu“or” 6.02 x atoms molecules or fu 1 mole

MOLE  VOLUME (for gasses) Molar Volume: The volume of 1 mole of gas at STP –STP (Standard Temperature and Pressure): 0  C and 1 atmosphere of pressure -Pressure and Temperature affect the volume of a gas 1 mole = 22.4 L 1 L = 1 dm 3 The conversion factors are: 1 moleor22.4 L 22.4 L1 mole

To Convert b/w Units Write the measurement given (# & unit) Times a line Insert the correct conversion factor so –Units cancel –The unit you want to convert to is on top Do the math. Check your answer’s unit—is it what you are looking for?

Opener: How many seconds are in 20 years?

1 mole = 6.02 x particles (atoms, molecules or formula units) 1 mole = molar mass (grams) 1 mole = 22.4 L (dm 3 ) a) How many molecules are in 2 moles of water? 1)What you know times a line 2)Appropriate conversion--units cancel 3)Do the math 4)Check your unit

1 mole = 6.02 x particles (atoms, molecules or formula units) 1 mole = molar mass (grams) 1 mole = 22.4 L (dm 3 ) b) You have an 11.2 g sample of table salt. How many moles of salt do you have? 1)What you know times a line 2)Appropriate conversion--units cancel 3)Do the math 4)Check your unit

1 mole = 6.02 x particles (atoms, molecules or formula units) 1 mole = molar mass (grams) 1 mole = 22.4 L (dm 3 ) c) A student fills a 5.0 L flask with carbon dioxide gas at standard temperature and pressure. How many moles of gas are in the flask? 1)What you know times a line 2)Appropriate conversion--units cancel 3)Do the math 4)Check your unit

1 mole = 6.02 x particles (atoms, molecules or formula units) 1 mole = molar mass (grams) 1 mole = 22.4 L (dm 3 ) d)How many moles is equivalent to 16.3 grams of lithium bromide? 1)What you know times a line 2)Appropriate conversion--units cancel 3)Do the math 4)Check your unit

1 mole = 6.02 x particles (atoms, molecules or formula units) 1 mole = molar mass (grams) 1 mole = 22.4 L (dm 3 ) e) A piece of marble contains 8.74 x formula units of calcium carbonate. How many moles of calcium carbonate is that? 1)What you know times a line 2)Appropriate conversion--units cancel 3)Do the math 4)Check your unit

f)265 grams g)2.2 x atoms h)1.6 x 10 2 L (same as 160 L) 1 mole = 6.02 x particles (atoms, molecules or formula units) 1 mole = molar mass (grams) 1 mole = 22.4 L (dm 3 )

a)How many grams of calcium are present in 7.2 x atoms of calcium? 1 mole = 6.02 x particles (atoms, molecules or formula units) 1 mole = molar mass (grams) 1 mole = 22.4 L (dm 3 )

b) You need 250 grams of table sugar, or sucrose (C 12 H 22 O 11 ), to bake a cake. How many sucrose molecules will be in the cake? 1 mole = 6.02 x particles (atoms, molecules or formula units) 1 mole = molar mass (grams) 1 mole = 22.4 L (dm 3 )

c) How many formula units of magnesium chloride are in 1.8 grams of magnesium chloride? d) 1.5 x 10 2 L (or 150 L) 1 mole = 6.02 x particles (atoms, molecules or formula units) 1 mole = molar mass (grams) 1 mole = 22.4 L (dm 3 )

OPENER: What percentage of the ceiling tiles are lights?

Percent Composition: % by mass of an element in a compound Purpose of Calculating % Comp: It’s the 1 st step in determining the chemical formula of a compound from the mass of its elements. To Calculate % Composition: –The % Composition is determined for each element in a compound –Experimental Data: Mass of Element ÷ Total Mass of Compound x 100% –Non-Experimental Data: Mass of Element ÷ Molar Mass of Compound x 100%

What is the % composition of water? A sample of unknown compound with a mass of g is extracted from the roots of a plant. Decomposition of the sample produces g of carbon, g of oxygen and g of hydrogen. What is the percent composition of the compound? c) 57.5% Na, 40.0% O, and 2.50% H Experimental Data: Mass of Element ÷ Total Mass of Compound x 100% Non-Experimental Data: Mass of Element ÷ Molar Mass of Compound x 100%

DAILY QUIZ—DAY 3 Do on back of current quiz A 90 g sample of a sodium/oxygen contains 53 g Na and 37 g O. What is the percent composition of this compound?

OPENER When the two met, one was half the other's age plus seven years. Ten years later, when they married, the bride was thirty, but this time one was nine- tenths the age of the other. How old was the groom? ( no fractions, no partial years---whole numbers only.)

ATB You are a bus driver. At the first stop, 4 people get on. At the second stop, 8 People get on. At the third stop, 2 people get off, and at the last stop, everyone gets off. The question is: What color are the bus drivers eyes? Explain your answer!

Empirical Formula The simplest whole number ratio of a chemical formula Determine the empirical formula for each of the following compounds: a) C 6 H 12 O 6 b) CH 4 c) N 2 O 4 d) H 2 O 2

Empirical Formula The empirical formula can be determined using: percent composition or mass & molar mass To determine an empirical formula: –Assume %’s are out of 100 g and change the unit % to the unit g –Determine the # of moles of each element –Determine the lowest whole # ratio of the moles of elements in the compound Easiest way: Divide all mole values by the lowest mole value

Examples of Empirical Formulas A compound was analyzed and found to contain 13.5 g Ca, 10.8 g O and g H. What is the empirical formula of the compound? Assume %’s are out of 100 g and change the unit % to the unit g Determine the # of moles of each element Determine the lowest whole # ratio of the moles of elements in the compound Easiest way: Divide all mole values by the lowest mole value

Determine the empirical formula for a compound containing g Cl and g Ca. C) Na 2 SO 3 Examples of Empirical Formulas Assume %’s are out of 100 g and change the unit % to the unit g Determine the # of moles of each element Determine the lowest whole # ratio of the moles of elements in the compound Easiest way: Divide all mole values by the lowest mole value

OPENER Mom, Dad, and 2 kids have come to a river, and they find a boat. It is small and can only carry one adult or 2 kids at a time. Both kids are good rowers, but how can the whole family reach the other side of the river?

MOLECULAR FORMULA: Indicates the # of each atom in a molecular compound The molecular formula is always: a whole # multiple of the empirical formula To determine the molecular formula: 1.Determine the empirical formula 2.Find the molar mass of the empirical formula 3.Divide the molar mass of the compound by the mass of the empirical formula to find a whole # 4.Multiply the subscripts in the empirical formula by the whole # found in step 3 to give the molecular formula 5.Check your work by checking the molar mass of the molecular formula

EXAMPLES OF MOLECULAR FORMULAS To determine the molecular formula: 1.Determine the empirical formula 2.Find the molar mass of the empirical formula 3.Divide the molar mass of the compound by the molar mass of the empirical formula to find a whole # 4.Multiply the subscripts in the empirical formula by the whole # found in step 3 to give the molecular formula 5.Check your work by checking the molar mass of the molecular formula 1) Ribose has a molar mass of 150 g/mol and a chemical composition of 40.0% carbon, 6.67 hydrogen and 53.3% oxygen. What is the molecular formula for ribose.

EXAMPLES OF MOLECULAR FORMULAS To determine the molecular formula: 1.Determine the empirical formula 2.Find the molar mass of the empirical formula 3.Divide the molar mass of the compound by the molar mass of the empirical formula to find a whole # 4.Multiply the subscripts in the empirical formula by the whole # found in step 3 to give the molecular formula 5.Check your work by checking the molar mass of the molecular formula 2)Find the molecular formula for a compound that contains 4.90 g N and 11.2 g O. The molar mass of the compound is 92.0 g/mol. 3)C 40 H 56

DAILY QUIZ DAY 4 Acetylene is an effective and versatile fuel gas. It is 92.3% carbon and 7.7% hydrogen. The molar mass is approximately 26 g/mol. What is the molecular formula of acetylene?

ATB: How many molecules are in x formula units of calcium chloride?

ATB What is the empirical formula of the compound that contains 0.25 mol oxygen and 0.10 mol nitrogen?

ATB: How many molecules are in 1.23 x moles of carbon monoxide?

1 mole = 6.02 x particles (atoms, molecules or formula units) 1 mole = molar mass (grams) 1 mole = 22.4 L (dm 3 )