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Avogadro’s Number. 6.02x10 23. mole = (mol) 602000000000000000000000. Mole. A mole is just a number like… Pair = 2 Trio = 3 Dozen = 12 Baker’s dozen = 13 Gross = 144 Score= 20 Century=100 Ream=500. How BIG is a mole?. There are ~ 6.6 billion people on Earth
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Avogadro’s Number 6.02x1023
mole = (mol) 602000000000000000000000 Mole • A mole is just a number like… Pair = 2 Trio = 3 Dozen = 12 Baker’s dozen = 13 Gross = 144 Score= 20 Century=100 Ream=500
How BIG is a mole? There are ~ 6.6 billion people on Earth How many Earths would it take to equal the population of 1 mole? 9.12 x 1013
If you spent $800 billion dollars a day how many years would it take to spend a MOLEion dollars? 2.06 x 109 years
If you had a mole of cats . . . They would create a sphere larger than Earth!
If you had a mole of H2O could you swim in it? NO! Water molecules are so small that a mole of H2O = 18ml
In chemistry we don’t work with individual atoms or molecules because they are too small to be weighed or measured • We have to work with LOTS of atoms in order to measure them THAT’s WHERE THE MOLE COMES IN!
How small are atoms? • There are more atoms in one gram of salt than grains of sand on all the beaches of all the oceans in all the world.
of the in Gram ATOMic Mass • mass is in grams of 1 mole of atoms of an element • In other words…… 1 mol C atoms = 6.02 x 10 23 C atoms = 12g C
PracticeRemember . . .1 mole = 6.02x1023atoms or molecules =______ g from the periodic table
of the in Gram Formula MassGram Molecular Mass Molar Mass • mass in grams of 1 mole of a substance • In other words . . . Add it all up! 1 mole of NaCl = 58g = 6.02x1023 particles of NaCl 1 mole of H2O = 18g = 6.02x1023 molecules of H20
Now….. • Use the gram formula mass and the gram atomic mass to determine • how many moles or atoms of an element are found in some mass of a substance • how much mass that element contributes to the mass of the entire substance Use factor label & follow the units!
Stoichiometry of Chemical Formulas • If you have 1 molecule of (NH4)2SO4 • How many atoms of N are there? • How many atoms of H? SO….. • If you have 1 mole of of (NH4)2SO4 • How many moles of N are there? • How many moles of H?
PracticeRemember . . .1 mole = 6.02x1023atoms or molecules =______ gfm from the pt
Gases ONLY @STP Molar Volume • 1 mole of ANYgas O2 (g) NH3 (g) He (g) contains 6.02 x 1023 molecules and occupies a volume of 22.4L
STP standardtemperature & pressure 0oC or 273K 101.3kPa or 1 atm
Remember . . . • Gases also have mass 1 mole of O2(g) = 32g 1 mole of NH3(g) = 17g we can calculate Density!
D = m/v • A sample of oxygen contains 3 moles of particles at STP what is its density? • 2 steps • Convert moles to mass AND volume • Calculate density • If mass or volume is given, use it and convert the other……. THEN calculate D!
Remember . . . 1 mole = 6.02x1023atoms or molecules =gfm = 22.4L (g)
“it’s a simple matter of weight ratios . . .” Stoichiometry of Chemical Equations • The study of quantitative relationships that can be derived from chemical equations.
Stoichiometry cookies • If you look at chemical equations as recipes it may be easier to understand that • changing the amount of a reactant will change the amount of the product IN THE SAME RATIO!
Examining Molar Relationships in Balanced Equations 6CO2 + 12 H2O + 2804kJ 6O2 + C6H12O6 +6H20 Balanced equations • Law of conservation of mass / matter • ATOMS are not createdor destroyed during a chemical reaction, they are only rearranged to form new substances. • # atoms on reactant side = # atoms on product side • Law of conservation of E • E on the reactant side = E on the product side
Mole - Mole Relationships Practice
