Law of definite composition A compound contains the same elements in exactly the same mass...
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Transcript of Law of definite composition A compound contains the same elements in exactly the same mass...
Law of definite compositionA compound contains the same elements in
exactly the same mass proportions
regardless of the size or source of sample.
The Law of Definite Proportions9.5 The Laws Governing Formulas and Names
Example…
The Law of Definite Proportions9.5 The Laws Governing Formulas and Names
Formula for magnesium sulfide __________ MgS
Ratio of Mg2+ to S2- ions ________ 1:1
Ratio of Mg2+ to S2- mass _______________ 24.305 : 32.066
For every ______ g of Mg2+ there are always ______ g of S2- in MgS
0.751
Example…
The Law of Definite Proportions9.5 The Laws Governing Formulas and Names
If you had 100 g of MgS the mass ratio Mg:S is __________ 0.75 : 1
If you had 200 g of MgS the mass ratio Mg:S is __________ 0.75 : 1
Does MgS obey the Law of Definite Proportions? _________ Y
MASS RATIO ALWAYS 0.75 : 1
Law of multiple proportions
Applies to different compounds made from
the same elements (e.g. NO2 and N2O4 )
Mass ratio for the same elements in
different compounds can be expressed in
small whole numbers.
The Law of Multiple Proportions9.5 The Laws Governing Formulas and Names
Law of multiple proportions
The Law of Multiple Proportions9.5 The Laws Governing Formulas and Names
Formula for carbon monoxide __________ CO
Mass ratio of O to C ____________________ 16 : 12.011 → 1.33 : 1
Formula for carbon dioxide __________ CO2
Mass ratio of O to C ____________________ 32 : 12.011 → 2.66 : 1
Law of multiple proportions
The Law of Multiple Proportions9.5 The Laws Governing Formulas and Names
CO CO2
1.33 g : 1 gO : C
2.66 g : 1 gO : C
Mass ratio of C in CO to C in CO2
______________________________________________________1 g : 1 g → 1 : 1 (small whole number!!)
Mass ratio of O in CO2 to O in CO
______________________________________________________2.66 g : 1.33 g → 2 : 1 (small whole number!!)
Examples9.5 The Laws Governing Formulas and Names
Carbon reacts with oxygen to form two compounds. Compound A contains 2.41 g of carbon for each 3.22 g of oxygen. Compound B contains 6.71 g of carbon for each 17.9 g of oxygen. For a given mass of oxygen, what is the lowest whole number ratio of carbon in Compound A to Compound B?
COMPOUND A COMPOUND B
C 2.41 g 6.71 g
O 3.22 g 17.9 g
3.22 g O in A
2.41 g C in A
17.9 g O in B
6.71 g C in B
1 g O in A
0.75 g C in A
1 g O in B
0.37 g C in B
“A GIVEN MASS OF OXYGEN”
0.37 g C in B
0.75 g C in A
1 g C in B
2 g C in A
LOWEST RATIO IS 2:1
Examples9.5 The Laws Governing Formulas and Names
COMPOUND A COMPOUND B
Pb 2.98 g 9.89 g
O 0.461 g 0.763 g
0.461 g O in A
2.98 g Pb in A
0.763 g O in B
9.89 g Pb in B
1 g O in A
6.46 g Pb in A
1 g O in B
12.96 g Pb in B
“A GIVEN MASS OF OXYGEN”
12.96 g Pb in B
6.46 g Pb in A
2 g Pb in B
1 g Pb in A
LOWEST RATIO IS 1:2
Lead forms two compounds with oxygen. Compound A contains 2.98 g of lead and 0.461 g of oxygen. Compound B contains 9.89 g of lead and 0.763 g of oxygen. For a given mass of oxygen, what is the lowest whole number ratio of lead in Compound A to Compound B?
Chapter 9 Review• Vocab
– Monatomic/polyatomic– Cation/anion– Acid/base– Binary compounds (ionic/molecular)
• Bohr Diagrams• Lewis Dot Structures• Identifying charge by Group #• Identifying metal/nonmetal
Chapter 9 Review
• Naming – When to use roman numerals– When to use prefixes
• Ionic vs. Molecular
• Difference between name endings– ide– ate– ite
Chapter 9 Review
• How to identify – Acid/base/neither– Molecular/ionic
• Laws of multiple proportions• Laws of definite proportions (composition)• Table (like homework) ~10 compounds• Formula from name & Name from formula ~40• Draw Bohr diagrams and Lewis Dots• Mass ratio problem
Vocab Ions Formulas Names Misc
100 100 100 100 100
200 200 200 200 200
300 300 300 300 300
400 400 400 400 400
500 500 500 500 500
MISCELLANEOUS – 300
THIS ARTIST HOLDS THE RECORD FOR THE BIGGEST ALL-TIME SALES FOR A SOLO ARTIST
MICHAEL JACKSON
MISCELLANEOUS – 400
GROUP OF ATOMS THAT ARE THE MOST ABUNDANT AND
FORM BOTH IONIC AND COVALENT BONDS
NON-METALS