Stoichiometry and the mole- Your new bffl November , * 10 3 Objective: SWBAT perform stoichiometric conversions from mole to mass, from mass to mass Catalyst: How many basketballs are in a dozen? How many turkeys are in a dozen? How was your break? *This week… bring scientific calculators if you have them!
Exit Question What do you need to do to get where you want to be in this class?
Agenda Catalyst/Welcome Back Test Review/Tracking/Corrections OMG! YOUR NEW BFFL! The mole. Bring back the train tracks Exit Question
What is a mole to us chemists? A benign overgrowth of cells because of a failure in mitosis? NO! But gross… A rascly little rodent? NOOOO! A TV show featuring celebrities? NOOOOO! Then WHAT IS IT?????!!!???!?!?!???!!!!
The Mole Think of the term “ a dozen ”… How many donuts are in a dozen? How many eggs are in a dozen?
The Mole Just like a dozen refers to 12 objects …
The Mole Just like a dozen refers to 12 objects … … the mole refers to …
The Mole Just like a dozen refers to 12 objects … … the mole refers to … 6.02 x particles
The Mole This number is called Avogadro ’ s number … 6.02 x ,000,000,000,000,000,000,000
Avogadro ’ s Number 1 mol = 6.02 x atoms 1 mol = 6.02 x molecules Why do YOU think we would do this?
Interpreting Equations 4 Fe + 3 O 2 2 Fe 2 O 3 “4 moles of iron react with 3 moles of oxygen gas to produce 2 moles of iron(III) oxide” Coefficients in chemical reactions just refer to how many moles are reacting!
Interpreting Equations C 3 H O 2 3 CO 2 + 4H 2 O “1 mole of propane (C 3 H 8 ) reacts with 5 moles of oxygen gas to produce 3 moles of carbon dioxide and 4 moles of water”
How many moles needed? (moles – moles) C 3 H O 2 3 CO 2 + 4H 2 O If you start with 10.0 moles of propane (C 3 H 8 ), how many moles of oxygen gas is needed to fully combust (react)?
How many moles produced? (moles – moles) C 3 H O 2 3 CO 2 + 4H 2 O If you start with 10.0 moles of propane (C 3 H 8 ), how many moles of carbon dioxide will be produced?
What’s the point of all this? Key Point #1: Stoichiometry relates the amount of REACTANTS with the amount of PRODUCTS. It all relates back to the mole… Scientists use stoichiometry to plan reactions! And guess what else is coming back….
TRAIN TRACKS!!! Step 1: What to what? Step 2: Write conversion factor(s) Step 3: Train tracks
Avogadro ’ s Number 1 mol = 6.02 x atoms How many atoms are in.25 mol N 2 ?
Avogadro ’ s Number 1 mol = 6.02 x atoms How many atoms are in.25 mol N 2 ?.25 mol N 2
Avogadro ’ s Number 1 mol = 6.02 x atoms How many atoms are in.25 mol N 2 ?.25 mol N 2 1 mol N x atoms I guess you can use your calculator for this…
Your turn! Whiteboards. How many atoms are in 1.1 moles of C 12 H 22 O 11 ?
OOOH, I want some more train tracks! Key Point #2: Molar mass the amount of grams in the mole of a substance. But Mr. J, how am I ever going to find out this information?
Molar Mass 1 mol C =
Molar Mass 1 mol C = 12 g C
Molar Mass The atomic weight of an atom is also the molar mass of that atom. Carbon has an atomic weight of In 1 mole of carbon, there are grams. In 1 mole of sodium, how many grams are there?
Molar Mass 1 mol Na =
Molar Mass 1 mol Na = 23 g Na
Molar Mass-Can you figure out this one?? 1 mol CO 2 =
Molar Mass 1 mol CO 2 = C = 12 gO = 16 gO = 16 g
Molar Mass 1 mol CO 2 = C = 12 g+ O = 16 g + O = 16 g
Molar Mass 1 mol CO 2 = 44 g CO 2 C = 12 g+ O = 16 g + O = 16 g
Molar Mass 1 mol KNO 3 = K = + N = + O =
Molar Mass 1 mol KNO 3 = K = 39 g + N = 14 g + (3) O = 16 g
Molar Mass 1 mol KNO 3 = 101 g K = 39 g + N = 14 g + (3) O = 16 g
Molar Mass- Let’s try a problem 1 mol KNO 3 = 101 g If we have 3.5 moles of KNO 3, how many grams would we have?
Molar Mass 1 mol CH 4 = If we have 20 grams CH 4, how many moles of CH 4 do we have?
Independent Practice 1, 11, 16… we will go over to show you how to solve this hilarious assignment! Attach your work on a separate sheet of paper.
Exit Question How many molecules are in a mole of NH 4 ? How many grams are there in 2.3 moles of NH 4 ?