7.1 Mole: the measurement of matter

Journal: You are working a job paying $10 per hour. Your regular shift is 5 hours long. How much do you earn in one shift?

$ 10 5 hours = $ 50 hour

Journal: You are working a job paying $10 per hour. Your regular shift is 5 hours long. How much do you earn in one shift? $ 10 5 hours = $ 50 hour

How much do you earn when you work 3 of the above mentioned shifts?

$ 50 3 shifts = $ 150 shift

We can apply the same problem solving concepts to measuring matter!!!! In real life 1 dozen donuts = ?

Mole Abbreviated mol Unit that measures the amount of the substance that a chemist is working with. Represents 6.02 x particles of a substance or representative unit. This value is called Avogadro’s Number – The substance can be atoms, molecules, or ions)

Avogadro’s Number 6.02 x particles Where did this number come from???? o Originates from the # of atoms in 12 grams of Carbon-12 o There are 6.02 x atoms of Carbon in 12 g of Carbon

1 mol = 6.02 x units 1 mol or 6.02 x units 6.02 x “units” 1 mol The “units” or representative particles can be: – Atoms (Hydrogen, H) – Particles (H 2 O) – formula units (OH - ) Write down all of this information in your handout!!! (Before we get to problem solving!!!)

This conversion can be used to convert between: atoms, molecules, or representative formula units and the Mole Mole atoms Atomsmole Moleculesmole Molemolecules

Problem solving 1. Problem asks to find and you are given atoms. Example: 1. How many moles of atomic nitrogen, N, are in 3 x atoms of nitrogen? Your problem solving conversion will require atoms to be canceled and the remaining unit will be moles.

How many moles of atomic nitrogen, N, are in 3 x atoms of nitrogen? 3 x atoms N 1 mol N 6.02 x atoms N = 0.5 moles N The reverse of this problem would be finding atoms in a set amount of moles.

2. Second type of problem: Finding atoms and you are given moles of a compound of a molecule Example: How many atoms are in 4 mol of ethane (CH 4 )? Given: 4 mol CH 4 We know: 1 mol CH 4 = 6.02 x molecules CH 4 Also 1 molecule of CH 4 = 5 atoms

How many atoms are in 4 mol of ethane (CH 4 )? Road map for conversion Mol  molecules  atoms 4 mol CH x molecules 5 atoms CH 4 1 mol CH 4 1 molecule CH 4 Solve without calculators!!!!

How many atoms are in 4 mol of ethane (CH 4 )? Road map for conversion Mol  molecules  atoms 4 mol CH x molecules 5 atoms CH 4 1 mol CH 4 1 molecule CH 4 Solve without calculators!!!! 1.2 x atoms

Your Turn!!!! How many moles are in 2.0 x molecules of NO 2 ? Given: Know:

Your Turn!!!! How many moles are in 2.0 x molecules of NO 2 ? Given: 2.0 x molecules NO 2 ? Know: 1 mole NO x molecules NO 2

Your Turn!!!! How many moles are in 2.0 x molecules of NO 2 ? Given: 2.0 x molecules NO 2 ? Know: 1 mole NO x molecules NO x molecules NO 2 1 mole NO x molecules NO 2

How many atoms are in 3 mol of H 2 O? Given: 3 mol of H 2 O Know: Hint** Road map mol  molecules  atoms

How many atoms are in 3 mol of H 2 O? Given: 3 mol of H 2 O Know: 6.02 x molecules H 2 O = 1 mol H 2 O 3 atoms H 2 O = 1 molecule H 2 O Hint** Road map mol  molecules  atoms

How many atoms are in 3 mol of H 2 O? Given: 3 mol of H 2 O Know: 6.02 x molecules H 2 O = 1 mol H 2 O 3 atoms H 2 O = 1 molecule H 2 O Hint** Road map mol  molecules  atoms 3 mol of H 2 O 6.02 x molecules H 2 O 3 atoms H 2 O 1 mol H 2 O 1 molecule H 2 O

FYI: Gram Formula Mass and Gram molecular mass are interchangeable!!!! Finding the mass of a compound: i.Identify the number of atoms of each element ii.Multiply the amount of each element by the atomic mass unit (amu) as found on the periodic table iii.Add up the amount for each element to find the total mass for the compound.

Example: Find the mass of CH 4 1 C + 4 H 1 (12 amu C) + 4 (1 amu H) = 16 amu total Your turn!

Your Turn!!! Find the mass of glucose C 6 H 12 O 6.

Practice In class Handout 7.1