Mr. Bimber Freedom High School We got Moles! Mr. Bimber Freedom High School

Warm up questions What is the smallest bit of an element? What is the smallest bit of a compound? Which heavy subatomic particles are in the nucleus? What is average sum of the heavy particles called? How many oxygen atoms are there in 2 molecules of Al(SO4)3 ? Atom Molecule Protons and Neutrons Atomic mass 24 (2 X 4 X 3)

Moles can be fun!

Today you will learn: What a mole is. What a mole lets chemists do. How to convert atoms and moles. How to convert moles and grams. What else moles can convert. Why moles are so important to chemists.

The “Big Picture” A mole is a big number, just like a dozen is a number. But a mole is much bigger: 1 mole = 6.02 X 1023 Moles let us count atoms.

This is important because: Moles let us change equations into units we can actually measure in the lab, like: Grams Liters Moles are in the middle of almost all chemistry problems.

What is a mole? A mole is just a really BIG number: 602,000,000,000,000,000,000,000 This is sometimes called “Avogadro’s Number.” How big is that? a mole of pennies in one stack would reach up past the moon! to count up to one mole would take centuries. Moles let us count atoms. Moles change atoms to things we can measure.

Moles let us convert between: Grams Liters of liquids Liters of gas Atoms Molecules Ions Subatomic particles Moles are in the middle of all these conversions:

Moles to Grams Atomic mass is the average number of protons and neutrons. It’s also the number of grams in one mole of atoms. To change from moles to grams, multiply by atomic mass. One mole of carbon atoms weighs 12.01 grams. 3 moles of C atoms weighs (3X12.01)= 36.03 g. 5 moles of Mg weighs (5X24.3+= 121.5 grams.

Grams to moles To change grams to moles, divide by atomic mass. 4 grams of Helium is (4/4) = 1 mole 20 g of He is (20/4) = 5 moles 50 g of Carbon is (50/12) = 4.17 moles

Other mole conversions One mole of any gas at standard temperature and pressure is 22.4 liters One mole equals 6.02 X1023 atoms, molecules or subatomic particles. One liter of any “one molar” solution has one mole of molecules dissolved in it.

Why moles matter Moles let you change formulas and equations into units you can actually measure, like grams and liters. Moles let you “count atoms”, without actually counting them.

Tips for the “mole math” ahead… Mole math is dimensional analysis. You’ll need to do math with exponents. Always write unit labels. A mole is just a number. 1 mole = Avogadro’s #. Show your work.

Summary 1 mole = 6.02 X 1023 = Avogadro’s number Moles let you connect formulas and equations with measured units, like grams and liters. To do “Mole Math”: Write numbers and units Use Dimensional Analysis

Get it? How much is 1 mole? How do you change moles into grams? How do you change grams into moles? 6.02 X 1023 Multiply by atomic mass. Divide by atomic mass.