Moles, Atoms, Molecules 10C
Chem I Ch 10 Notes/ Chem I H chapter 11 notes
10A
The atomic mass is found by checking the periodic table.
The atomic mass is the number of grams of an element that is numerically equal to the mass of an atomic mass unit. atomic mass C = 12.0 g
The atomic mass is the mass of one mole of atoms.
Mole – quantity such that there are as many atoms as in 12 g of carbon
The mass of a mole of NaCl is the molar mass.
1 atom 1 mole 1 molecule 1 mole
C 12.0 u 12.0 g Cl2 2Cl 2 X 35.5u = 71.0u 71.0 g
Fe 55.8 u 55.8 g H2O 2H 2 X 1.0u = 2.0u
Cu 63.5 u 63.5 g 1O 1 X 16.0u = 16.0u 18.0 g
18.0u
C3H6 3C 3 X 12.0u=36.0u
6H 6 X 1.0u= 6.0u 42.0 g
42.0u
1 formula unit 1 mole
2Al, 2 X 27.0u = 54.0u
Al2(SO4)3 3S, 3 X 32.1u = 96.3u 342.3 g
12 O, 12 X 16.0u = 192.0u
342.3u
Notes Converting grams to moles 10B
To convert first write what you are given.
Then “times sign draw a line”.
Place what you want above the line and the given below the line.
“mol” always has a coefficient of 1.
Where you see “g”, go to the periodic table to find the value.
Ex 1 How many grams are in 6.50 moles of H2SO4?
[pic] 2H 2 X 1.0 = 2.0g
1S 1 X 32.1 = 32.1g
4 O 4 X 16.0 = 64.0g
98.1g
Ex 2 What is the mass in grams of 5.90 mol C8H18? 8C 8 X 12.0 = 96.0g
[pic] 18H 18 X 1.0 = 18.0g
[pic] 114.0g
Ex 3 What is the number of moles in 432 g Ba(NO3)2?
1 Ba 1 X 137.3 = 137.3g
2 N 2 X 14.0 = 28.0g
6 O 6 X 16.0 = 96.0g
261.3g
[pic][pic]
Moles, Atoms, Molecules 10C
Representative particle - atom, molecule, or formula unit.
A mole of a substance contains
6.02 X 1023 representative particles
Avogadro’s number = 6.02 X 1023
Mole – SI unit used to measure number of representative
particles in a substance
A dozen is to eggs as mole is to atoms.
Conversion questions to answer – What’s the unknown
What is given
How many times signs
Molecules will always have 1 or 6.02 X 1023
EX 1
How many moles of magnesium is 1.25 X 1023 atoms of magnesium?
[pic]
EX 2
How many atoms are in 2.12 mol of C3H8 (propane)?
[pic]
Percent Composition 10D
[pic]
[pic]
Ex 1
Find the % composition of C3H8.
3C 3 X 12.0 = 36.0g
8H 8 X 1.0 = 8.0g
44.0g
[pic]
[pic]
Ex 2
What is the percentage of nitrogen in NH3?
1N 1 X 14.0 = 14.0g
3H 3 X 1.0 = 3.0g
17.0g
[pic]
Empirical Formulas 10E
Empirical formula – lowest whole-number ratio of the elements
in a compound (divide by – Greatest Common Factor)
CNH4 not C2N2H8
Empirical Formula Calculations
Change the given information to moles for each
element.
Divide each mole answer by the smallest
number of moles.
If the answers from step 2 are not whole numbers
then divide by the smallest decimal part.
Write the formula with the mole ratio as subscripts.
EX 1 Find the empirical formula. A compound contains
9.31g of Ag and 0.69g of O.
[pic]
[pic] Ag2O
EX 2 A compound contains 25.9% N and 74.1% O.
Find the empirical formula.
[pic] 1(.5 = 2
[pic] 2.50 ( .5 = 5
N2O5
Molecular Formulas 10F
Molecular formula – empirical formula or its multiple
Several compounds can have the same empirical formula but different molecular formulas.
Convert molecular ( empirical
Divide subscripts by greatest common factor
empirical ( molecular
multiply subscripts by [pic]
EX 1
The empirical formula is CH4N and the molar mass is 60.0 g. Find the molecular formula.
C 1 X 12.0 = 12.0g
4H 4 X 1.0 = 4.0g [pic] C2H8N2
N 1 X 14.0 = 14.0g
30.0g
EX 2
Find the molecular formula of C4H6O if the molar mass is 280.0g.
4C 1 X 12.0 = 48.0g
6H 4 X 1.0 = 6.0g [pic] C16H24O4
O 1 X 14.0 = 16.0g
70.0g
Name______________________Pd._____ Date_________ Chem I H Chapter 11 Notes/ Chem I Chapter 10 Notes
10A
The atomic mass is found by checking the __________ ______.
The _____________ ________ is the number of grams of an element that is numerically equal to the mass of an atomic mass unit. (atomic mass C = 12.0 g)
The atomic mass is the mass of one ____________ of atoms.
Mole – quantity such that there are as many atoms as in 12 g of carbon
The mass of a mole of NaCl is the ______________ ________.
1 atom 1 mole 1 molecule 1 mole
C 12.0 u 12.0 _ Cl2 2Cl 2 X 35.5u = 71.0 _
Fe 55.8 u 55.8 _ H2O 2H 2 X 1.0u =
Cu 63.5 u 63.5 _ 1 O 1 X 16.0u =
C3H6 3C 3 X
6H 6 x
1 formula unit 1 mole
Al________________________
Al2(SO4)3 S________________________
O ________________________
Ch 10 Notes Converting grams to moles 10B
To convert first write what you are ______________________.
Then “times sign__________________________________”.
Place what you want above the line and the given below the line.
“mol” always has a coefficient of __________.
Where you see “g”, _______ to the periodic table to find the value.
Ex 1 How many grams are in 6.50 moles of H2SO4? Show all work
2H ____________________
1S ____________________
________________________ 4 O ____________________
____________________
Ex 2 What is the mass in grams of 5.90 mol C8H18? 8C__________
____________
[pic]______________________________ g
Ex 3 What is the number of moles in 432 g Ba(NO3)2?
Ba
N
O
_____________________________________
Moles, Atoms, Molecules 10C
Representative particle - atom, molecule, or _________ _____
A mole of a substance contains
____________________ representative particles
Avogadro’s number = ______________________
_________– SI unit used to measure number of representative
particles in a substance
A dozen is to eggs as mole is to atoms.
Conversion questions to answer – What’s the ______________
What is given
How many times _________
Molecules will always have 1 or ___________________
EX 1
How many moles of magnesium is 1.25 X 1023 atoms of magnesium?
___________________________________________
EX 2
How many atoms are in 2.12 mol of C3H8 (propane)?
___________________________________________
Percent Composition 10D
[pic]
[pic]
Ex 1
Find the % composition of C3H8.
3C ______________
8H ______________
_____
_____________________________
_____________________________
Ex 2
What is the percentage of nitrogen in NH3?
1N ______________
3H ______________
_____
_____________________________
Empirical Formulas 10E
Empirical formula – lowest __________________
ratio of the elements in a compound
(divide by – Greatest Common Factor)
i.e. CNH4 not C2N2H8
Empirical Formula Calculations
Change the given information to __________ for each
element.
Divide each mole answer by the _________________
number of moles.
If the answers from step 2 are not whole numbers
then divide by the smallest decimal part.
Write the formula with the mole ratio as ___________.
EX 1 Find the empirical formula. A compound contains
9.31g of Ag and 0.69g of O.
9.31 g Ag X
0.69 g O X
Which answer is the smallest number?____________________
[pic]
[pic] ______________________
EX 2 A compound contains 25.9% N and 74.1% O.
Find the empirical formula. (Hint: change % to grams)
Molecular Formulas 10F
Molecular formula – empirical formula or its ______________
Several compounds can have the same _____________ _____
but different molecular formulas.
Convert molecular ( empirical
Divide subscripts by ______________ __________ _________
empirical ( molecular
multiply subscripts by ___________________
EX 1
The empirical formula is CH4N and the molar mass is 60.0 g. Find the molecular formula.
C 1 X 12.0 = 12.0g
4H 4 X 1.0 = 4.0g
N 1 X 14.0 = 14.0g __________________
30.0g
EX 2
Find the molecular formula of C4H6O if the molar mass is 280.0g.
4C 1 X 12.0 = 48.0g
6H 4 X 1.0 = 6.0g
O 1 X 14.0 = 16.0g ____________________
70.0g
Ch 10 Test Reference
Percent Composition [pic]
Empirical Formula Calculations
Change the given information to moles for each
element.
Divide each mole answer by the smallest
number of moles.
If the answers from step 2 are not whole numbers
then divide by the smallest decimal part.
Write the formula with the mole ratio as subscripts.
Convert molecular ( empirical
Divide subscripts by greatest common factor
Convert empirical ( molecular
multiply subscripts by [pic]
................
................
In order to avoid copyright disputes, this page is only a partial summary.
To fulfill the demand for quickly locating and searching documents.
It is intelligent file search solution for home and business.
Related searches
- atoms to molecules conversion
- molecules to moles conversion
- atoms to moles to grams calculator
- atoms and molecules worksheets
- atoms and molecules worksheet answers
- atoms and molecules worksheet pdf
- atoms and molecules worksheet key
- atoms and molecules pdf
- atoms molecules elements compounds kids
- molecules to moles conversion calculator
- atoms molecules and compounds worksheet
- molecules to moles calculator