the mole contents what is a mole and why do we use it? calculating the number of moles of a single...
TRANSCRIPT
THE MOLETHE MOLE CONTENTS
• What is a mole and why do we use it?
• Calculating the number of moles of a single substance
• Reacting mass calculations
Before you start it would be helpful to…
• know how to balance simple equations
• know how to re-arrange mathematical formulae
THE MOLETHE MOLE
DON’T BE LEFT IN THE
DARK!
WHAT IS A MOLE ?
it is the standard unit of amount of a substance - it is just a number, a very big numberit is a way of saying a number in words, just like...
DOZEN for 12 SCORE for 20 GROSS for 144
THE MOLETHE MOLE
HOW BIG IS IT ?
602200000000000000000000 (Approximately)... THAT’S BIG !!!
It is a lot easier to write it as... 6.022 x 1023
THE MOLETHE MOLE
WHAT IS A MOLE ?
it is the standard unit of amount of a substance - it is just a number, a very big numberit is a way of saying a number in words, just like...
DOZEN for 12 SCORE for 20 GROSS for 144
HOW BIG IS IT ?
602200000000000000000000 (Approximately)... THAT’S BIG !!!
It is a lot easier to write it as... 6.022 x 1023
It is also known as... AVOGADRO’S NUMBER
It doesn’t matter what the number is as long as everybody sticks to the same value !
THE MOLETHE MOLE
WHAT IS A MOLE ?
it is the standard unit of amount of a substance - it is just a number, a very big numberit is a way of saying a number in words, just like...
DOZEN for 12 SCORE for 20 GROSS for 144
WHY USE IT ?
Atoms and molecules don’t weigh much so it is easier to count large numbers of them. In fact it is easier to weigh substances.
Using moles tells you... how many particles you get in a certain mass the mass of a certain number of particles
DO I NEED TO KNOW ANYTHING ELSE ?
Yes, it would help if you can balance equations
AND Keep trying, you will get the idea ... EVENTUALLY!
THE MOLETHE MOLE
WHAT IS IT? The standard unit of amount of a substance - just as the standard unit of length is a METREIt is just a number, a very big numberIt is also a way of saying a number in wordslike DOZEN for 12
GROSS for 144
THE MOLE – AN OVERVIEWTHE MOLE – AN OVERVIEW
WHAT IS IT? The standard unit of amount of a substance - just as the standard unit of length is a METREIt is just a number, a very big numberIt is also a way of saying a number in wordslike DOZEN for 12
GROSS for 144
HOW BIG IS IT ? 602200000000000000000000 (approx) - THAT’S BIG !!!It is a lot easier to write it as 6.022 x 1023
And anyway it doesn’t matter what the number isas long as everybody sticks to the same value !
THE MOLE – AN OVERVIEWTHE MOLE – AN OVERVIEW
WHAT IS IT? The standard unit of amount of a substance - just as the standard unit of length is a METREIt is just a number, a very big numberIt is also a way of saying a number in wordslike DOZEN for 12
GROSS for 144
HOW BIG IS IT ? 602200000000000000000000 (approx) - THAT’S BIG !!!It is a lot easier to write it as 6.022 x 1023
And anyway it doesn’t matter what the number isas long as everybody sticks to the same value !
WHY USE IT ? Atoms and molecules don’t weigh much so it iseasier to count large numbers of them.In fact it is easier to weigh substances.
Using moles tells you :- how many particles you get in a certain massthe mass of a certain number of particles
THE MOLE – AN OVERVIEWTHE MOLE – AN OVERVIEW
CALCULATING THE NUMBER OF MOLES OF A SINGLE SUBSTANCE
moles = mass / molar mass mass = moles x molar mass
molar mass = mass / moles
UNITS
mass g or kgmolar mass g mol-1 or kg mol-1
THE MOLETHE MOLE
MOLES = MASS MOLAR MASS MOLES = MASS MOLAR MASS
MASS
MOLES x MOLAR MASS
COVER UP THE VALUE YOU WANT AND THE METHOD
OF CALCULATION IS REVEALED
1. Calculate the number of moles of oxygen molecules in 4g
MOLES OF A SINGLE SUBSTANCEMOLES OF A SINGLE SUBSTANCE
1. Calculate the number of moles of oxygen molecules in 4g oxygen molecules have the formula O2
relative mass will be 2 x 16 = 32 ; molar mass will be 32g mol-1
MOLES OF A SINGLE SUBSTANCEMOLES OF A SINGLE SUBSTANCE
1. Calculate the number of moles of oxygen molecules in 4g oxygen molecules have the formula O2
relative mass will be 2 x 16 = 32 ; molar mass will be 32g mol-1
moles = mass = 4g = 0.125 mol molar mass 32g mol -1
MOLES OF A SINGLE SUBSTANCEMOLES OF A SINGLE SUBSTANCE
1. Calculate the number of moles of oxygen molecules in 4g oxygen molecules have the formula O2
relative mass will be 2 x 16 = 32 ; molar mass will be 32g mol-1
moles = mass = 4g = 0.125 mol molar mass 32g mol -1
MOLES OF A SINGLE SUBSTANCEMOLES OF A SINGLE SUBSTANCE
1. Calculate the number of moles of oxygen molecules in 4g oxygen molecules have the formula O2
relative mass will be 2 x 16 = 32 ; molar mass will be 32g mol-1
moles = mass = 4g = 0.125 mol molar mass 32g mol -1
2. What is the mass of 0.25 mol of Na2CO3 ?
MOLES OF A SINGLE SUBSTANCEMOLES OF A SINGLE SUBSTANCE
1. Calculate the number of moles of oxygen molecules in 4g oxygen molecules have the formula O2
relative mass will be 2 x 16 = 32 ; molar mass will be 32g mol-1
moles = mass = 4g = 0.125 mol molar mass 32g mol -1
2. What is the mass of 0.25 mol of Na2CO3 ?
Relative Molecular Mass of Na2CO3 = (2x23) + 12 + (3x16) = 106
Molar mass of Na2CO3 = 106g mol-1
MOLES OF A SINGLE SUBSTANCEMOLES OF A SINGLE SUBSTANCE
1. Calculate the number of moles of oxygen molecules in 4g oxygen molecules have the formula O2
relative mass will be 2 x 16 = 32 ; molar mass will be 32g mol-1
moles = mass = 4g = 0.125 mol molar mass 32g mol -1
2. What is the mass of 0.25 mol of Na2CO3 ?
Relative Molecular Mass of Na2CO3 = (2x23) + 12 + (3x16) = 106
Molar mass of Na2CO3 = 106g mol-1
mass = moles x molar mass = 0.25 x 106 = 26.5g
MOLES OF A SINGLE SUBSTANCEMOLES OF A SINGLE SUBSTANCE
1. Calculate the number of moles of oxygen molecules in 4g oxygen molecules have the formula O2
relative mass will be 2 x 16 = 32 ; molar mass will be 32g mol-1
moles = mass = 4g = 0.125 mol molar mass 32g mol -1
2. What is the mass of 0.25 mol of Na2CO3 ?
Relative Molecular Mass of Na2CO3 = (2x23) + 12 + (3x16) = 106
Molar mass of Na2CO3 = 106g mol-1
mass = moles x molar mass = 0.25 x 106 = 26.5g
MOLES OF A SINGLE SUBSTANCEMOLES OF A SINGLE SUBSTANCE