THE MOLE What a fun concept

WHAT IS A MOLE? A burrowing critter? A skin pigmentation? A word that evokes an enormous number? 1 mole of any substance equals 6.02 x representative particles of that substance 6.02 x is known as Avogadro’s number

WHAT IS A REPRESENTATIVE PARTICLE? It depends on what the substance is What can a substance be? Element Anything but the BrINClHOF elements which are diatomic molecules in nature Molecular compound Made of two or more nonmetals…includes BrINClHOF elements with their subscripts of 2 Ionic compound Made of a metal and a nonmetal or contains a polyatomic ion

A HANDY LITTLE CHART SubstanceRepresentative Particle (rp) Smaller bits ElementAtom Molecular CompoundMoleculeAtoms Ionic CompoundFormula UnitIons

SO, HERE WE GO… 1 mol of Fe contains 6.02 x atoms of Fe 1 mol of Br 2 contains 6.02 x molecules of Br 2 1 mol of NaCl contains 6.02 x formula units of NaCl 1 mol of SO 3 contains 6.02 x molecules of SO 3 1 mol of Na 2 O contains 6.02 x formula units of Na 2 O

AND WE MAKE THAT INFO USEFUL BY WRITING IT AS… 1 mol Fe 6.02 x atoms Fe 1 mol of Br x molec Br 2 1 mol of NaCl 6.02 x fu NaCl 1 mol of SO x molec SO 3 1 mol Na 2 O 6.02 x fu Na 2 O

OR WE CAN FLIP THEM TO GET… 6.02 x atoms Fe 1 mol Fe 6.02 x molec Br 2 1 mol of Br x fu NaCl 1 mol of NaCl 6.02 x molec SO 3 1 mol of SO x fu Na 2 O 1 mol Na 2 O

SMALLER BITS? Only for molecules and formula units 1 molec Br 2 has 2 atoms of Br 1 fu NaCl has 1 Na 1+ ion and 1 Cl 1- ion 1 molec SO 3 has 1 S atom and 3 O atoms 1 fu Na 2 O has 2 Na 1+ ions and 1 O 2- ion

MOLAR MASS The mass of one mole of a substance Use average atomic masses from the periodic table and round their masses to the hundredths place for consistency Unit is g/mol 1 mol Fe = g Fe …55.85 g Fe = 1 mol Fe 1 mol Feor55.85 g Fe g Fe1 mol Fe

MOLAR MASS OF A COMPOUND For a compound, you must calculate the molar mass Molar Mass of Br 2 Br---2 x = g/mol 1 mol Br 2 or g Br g Br 2 1 mol Br 2

MOLAR MASS OF A COMPOUND Molar Mass of NaCl Na---1 x = Cl--- 1 x = g/mol 1 mol NaClor58.44 g NaCl g NaCl 1 mol NaCl

MOLAR MASS OF A COMPOUND Molar Mass of SO 3 S---1 x = O---3 x = g/mol 1 mol SO 3 or80.06g SO g SO 3 1 mol SO 3

MOLAR MASS OF A COMPOUND Molar Mass of Na 2 O Na---2 x = O--- 1 x = g/mol 1 mol Na 2 O or61.98 g Na 2 O g Na 2 O 1 mol Na 2 O

MOLAR MASS OF A COMPOUND Molar Mass of Ca(OH) 2 Ca---1 x = O--- 2 x = H--- 2 x 1.01 = g/mol 1 mol Ca(OH) 2 or74.10 g Ca(OH) g Ca(OH) 2 1 mol Ca(OH) 2

MOLAR MASS OF A COMPOUND Molar Mass of Mg(C 2 H 3 O 2 ) 2 Mg---1 x = C--- 4 x = H--- 6 x 1.01 = 6.06 O--- 4 x = g/mol 1 mol Mg(C 2 H 3 O 2 ) 2 or g Mg(C 2 H 3 O 2 ) g Mg(C 2 H 3 O 2 ) 2 1 mol Mg(C 2 H 3 O 2 ) 2

ANOTHER HANDY CHART rpmass 1 mol

AND NOW, YOU PUT IT ALL TOGETHER How many atoms of helium are in 4.50 mol of helium? Is helium an element, molecular compound, or ionic compound? What is its representative particle? Use your given information to begin your dimensional analysis or unit conversion…always write a number, unit, and substance 4.50 mol He x 6.02 x atoms He = 2.71 x atoms He 1 mol He

SO, HAVE FUN If a sample of chlorine gas contains 2.97 x atoms of Cl, how many moles of chlorine gas are there? Is chlorine gas an element, molecular compound, or ionic compound? What is its representative particle? Use your given information to begin your dimensional analysis or unit conversion…always write a number, unit, and substance 2.97 x atoms Cl x 1 molec Cl 2 x 1 mol Cl 2 = 2 atoms Cl 6.02 x molec Cl 2

PRACTICING How many sulfide ions are present in 10.0 g of ferric sulfide? Is ferric sulfide an element, molecular compound, or ionic compound? What is its representative particle? Use your given information to begin your dimensional analysis or unit conversion…always write a number, unit, and substance 10.0 g Fe 2 S 3 x 1 mol Fe 2 S 3 x 6.02 x fu Fe 2 S 3 x g Fe 2 S 3 1 mol Fe 2 S 3 3 ions S 2- = 1 fu Fe 2 S 3