Conceptual Chemistry :Conceptual Chemistry Measuring Matter


Objectives :Objectives Define the mole and Avogadro’s Number. Convert between moles and number of particles.


Matter :Matter All matter is made of particles Atoms Molecules Diatomic elements Molecular compounds Ions Cations Anions Formula units of Ionic compounds


The Mole :The Mole Particles in matter are very small Too small to see Too small for a microscope Counting particles is not possible Chemists use the mole to count particles


The Mole :The Mole The mole is a unit for measuring the amount of a substance Mole is abbreviated mol One mole is 6.02 x 1023 particles


The Mole :The Mole Look at the objects on the lab bench. How are these groups of objects similar? Paper clips m & m’s Atomic models Pencils Beakers Books Tape dispensers Bottles


How many? :How many?


12 of each item :12 of each item


Another name for 12 items? :Another name for 12 items?


One dozen items = 12 items :One dozen items = 12 items


Everyone knows a dozen is 12 :Everyone knows a dozen is 12


The item doesn’t matter :The item doesn’t matter


1 dozen = 12 items :1 dozen = 12 items


2 dozen = 24 items :2 dozen = 24 items


The Mole :The Mole Look at the objects on the teacher’s desk. How are these groups of objects similar? 12 Paper clips 12 m & m’s 12 Atomic models 12 Pencils 12 Beakers 12 Books 12 Tape dispensers 12 Bottles


The Mole :The Mole You could say we have a dozen of each object. 1 dozen Paper clips 1 dozen m & m’s 1 dozen Atomic models 1 dozen Pencils 1 dozen Beakers 1 dozen Books 1 dozen Tape dispensers 1 dozen Bottles


The Mole :The Mole A dozen of any object would contain 12 of the objects. A mole is similar to a dozen The number of objects in a mole is a much larger number.


Number in a mole. :Number in a mole. The number is 602


Number in a mole. :Number in a mole. The number is 602 000


Number in a mole. :Number in a mole. The number is 602 000 000


Number in a mole. :Number in a mole. The number is 602 000 000 000


Number in a mole. :Number in a mole. The number is 602 000 000 000 000


Number in a mole. :Number in a mole. The number is 602 000 000 000 000 000


Number in a mole. :Number in a mole. The number is 602 000 000 000 000 000 000


Number in a mole. :Number in a mole. The number is 602 000 000 000 000 000 000 000


Number in a mole. :Number in a mole. The number is 602 000 000 000 000 000 000 000 We will write it as 6.02 x 1023


The Mole :The Mole A second name for the number 6.02 x 1023 is Avogadro’s number. Avogadro was a chemist who studied atoms and molecules and was among the first to explain the difference between atoms and molecules.


Mole-Particle Conversions :Mole-Particle Conversions If you have 6.02 x 1023 particles, you have 1.00 moles of particles. If you have 9.03 x 1023 particles, you have 1.50 moles of particles. If you have 3.01 x 1023 particles, you have 0.500 moles of particles.


Sample Problem :Sample Problem How many atoms are in 2.00 mol of argon?


Sample Problem :Sample Problem How many atoms are in 2.00 mol of argon? Use the factor label method to solve this problem.


Sample Problem :Sample Problem How many atoms are in 2.00 mol of argon? Use the factor label method to solve this problem. It will help you decide when to multiply or divide.


Sample Problem :Sample Problem How many atoms are in 2.00 mol of argon? Write the number from the problem in the space where you are going to show your work.


Sample Problem :Sample Problem How many atoms are in 2.00 mol of argon? Write the number from the problem in the space where you are going to show your work.


Sample Problem :Sample Problem How many atoms are in 2.00 mol of argon? Remember, the process is always written as multiplication.


Sample Problem :Sample Problem How many atoms are in 2.00 mol of argon? And, you always multiply by a fraction.


Sample Problem :Sample Problem How many atoms are in 2.00 mol of argon? The bottom of the fraction has a unit that matches the unit of the given amount from the problem.


Sample Problem :Sample Problem How many atoms are in 2.00 mol of argon? The top of the fraction has a unit that matches the unit in the question in the problem.


Sample Problem :Sample Problem How many atoms are in 2.00 mol of argon? Now, put the numbers in that make the top and bottom equal.


Sample Problem :Sample Problem How many atoms are in 2.00 mol of argon? Cross out the matching units.


Sample Problem :Sample Problem How many atoms are in 2.00 mol of argon? Finally, use the calculator


Sample Problem :Sample Problem How many atoms are in 2.00 mol of argon? Put the given number into the calculator.


Sample Problem :Sample Problem How many atoms are in 2.00 mol of argon? Multiply by the number on the top and divide by the number on the bottom. Read your calculator’s manual for instructions on putting this number into your calculator!


Sample Problem :Sample Problem How many atoms are in 2.00 mol of argon? Write the answer.


Sample Problem :Sample Problem How many moles are in 4.35 x 1024 molecules of carbon dioxide? Try this one.


Sample Problem :Sample Problem How many moles are in 4.35 x 1024 molecules of carbon dioxide? Start with the number from the problem.


Sample Problem :Sample Problem How many moles are in 4.35 x 1024 molecules of carbon dioxide? Set up the units of the conversion factor.


Sample Problem :Sample Problem How many moles are in 4.35 x 1024 molecules of carbon dioxide? Fill in the numbers to make the values of top and bottom equal.


Sample Problem :Sample Problem How many moles are in 4.35 x 1024 molecules of carbon dioxide? Cancel the units.


Sample Problem :Sample Problem How many moles are in 4.35 x 1024 molecules of carbon dioxide? Calculate the answer.


Sample Problem :Sample Problem How many formula units are in 3.15 mol of sodium oxide? Notice this asks for formula units since sodium oxide is ionic.


Sample Problem :Sample Problem How many formula units are in 3.15 mol of sodium oxide? Number from problem


Sample Problem :Sample Problem How many formula units are in 3.15 mol of sodium oxide? Put in the factor.


Sample Problem :Sample Problem How many formula units are in 3.15 mol of sodium oxide? Put in the factor.


Sample Problem :Sample Problem How many formula units are in 3.15 mol of sodium oxide? Calculate the answer.