Transcript Chemical formulas

Topic: Chemical Formulas
Essential Question: What is the law of
conservation of mass, and how does it apply
to chemical equations?
Topic: Chemical Formulas
Essential Question: What is the law of conservation of mass, and how
does it apply to chemical equations?
Chemical formulas
Are written using an elements
chemical symbol from the periodic
table
Used to identify how many atoms of
each element are present
Topic: Chemical Formulas
Essential Question: What is the law of conservation of mass, and how
does it apply to chemical equations?
Chemical formula for water
H 20
Subscript- tells you how many
atoms per element there are
There are 2 Hydrogen atoms and
1 Oxygen atom in water
Topic: Chemical Formulas
Essential Question: What is the law of conservation of mass, and how
does it apply to chemical equations?
Chemical formula for water
3H20
Coefficient- tells you how many
molecules there are
There are 3 molecules of water
Topic: Chemical Formulas
Essential Question: What is the law of conservation of mass, and how
does it apply to chemical equations?
Chemical formula for water
3H20
Coefficient- you multiply the
coefficient by the subscript to get
the number of atoms per element
There are 6 hydrogen atoms and
3 oxygen atoms
Topic: Chemical Formulas
Essential Question: What is the law of conservation of mass, and how
does it apply to chemical equations?
Law of conservation of mass
During a chemical reaction, no
matter is created or destroyed,
it is just rearranged
2H2 + O2  2H2O
H H
H H + O 
H H
O
O
H H
O
The chemical equation is balanced
Topic: Chemical Formulas
Essential Question: What is the law of conservation of mass, and how
does it apply to chemical equations?
How to see if a chemical equation is balanced
2H2 + O2  2H2O
H- 4
H- 4
O- 2
O- 2
1.) Take an element inventory for each
side of the equation
2.) Write down the number of atoms for
each element
3.) If the numbers match, then it is
balanced
Now take some time…
• Take 2 minutes to go over your notes and
highlight or underline the main ideas that
answer the essential question, you should not
highlight everything:
• Essential Question: What is the law of
conservation of mass, and how does it
apply to chemical equations?
Time to use the left hand column
• You will be writing your own questions from
now on!
• To get you started, verbs will be provided
Topic: Chemical Formulas
Essential Question: What is the law of conservation of mass, and how
does it apply to chemical equations?
Choose one verb
to write your
question:
Define
Describe
Compare
Explain
Chemical formulas
Are written using an elements
chemical symbol from the periodic
table
Used to identify how many atoms of
each element are present
Topic: Chemical Formulas
Essential Question: What is the law of conservation of mass, and how
does it apply to chemical equations?
Chemical formula for water
Choose one verb
to write your
question:
Define
Describe
Compare
Explain
H 20
Subscript- tells you how many
atoms per element there are
There are 2 Hydrogen atoms and
1 Oxygen atom in water
Topic: Chemical Formulas
Essential Question: What is the law of conservation of mass, and how
does it apply to chemical equations?
Chemical formula for water
Choose one verb
to write your
question:
Define
Describe
Compare
Explain
3H20
Coefficient- tells you how many
molecules there are
There are 3 molecules of water
Topic: Chemical Formulas
Essential Question: What is the law of conservation of mass, and how
does it apply to chemical equations?
Chemical formula for water
Choose one verb
to write your
question:
Define
Describe
Compare
Explain
3H20
Coefficient- you multiply the
coefficient by the subscript to get
the number of atoms per element
There are 6 hydrogen atoms and
3 oxygen atoms
Topic: Chemical Formulas
Essential Question: What is the law of conservation of mass, and how
does it apply to chemical equations?
Law of conservation of mass
Choose one verb
to write your
question:
Define
Describe
Compare
Explain
During a chemical reaction, no
matter is created or destroyed,
it is just rearranged
2H2 + O2  2H2O
H H
H H + O 
H H
O
O
H H
O
The chemical equation is balanced
Topic: Chemical Formulas
Essential Question: What is the law of conservation of mass, and how
does it apply to chemical equations?
Choose one verb
to write your
question:
Define
Describe
Compare
Explain
How to see if a chemical equation is balanced
2H2 + O2  2H2O
H- 4
H- 4
O- 2
O- 2
1.) Take an element inventory for each
side of the equation
2.) Write down the number of atoms for
each element
3.) If the numbers match, then it is
balanced
Time to use the left hand column
• You will now write questions on your own
using question starters that are provided
Now let’s write a summary
Look at each question you
wrote on your own, and
answer each question in
a complete sentence.