Chemical Formulas
Presentation
•
Science
•
8th Grade
•
Medium
Standards-aligned
Amber Gilbert
Used 3+ times
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13 Slides • 13 Questions
1
Chemical Formulas
How are chemical formulas used to identify substances?
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ELEMENTS
A chemical that cannot be broken down into another substance.
Each unique capital letter represents a different element.
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ELEMENTS
How many elements are in glucose?
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ATOMS
The smallest part of a chemical element.
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MOLECULES
Combining atoms creates molecules.
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Formula for Molecules
An expression which states the number and type of atoms present in a molecule of a substance.
*H2 tells you there are 2 atoms of hydrogen.
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H2O tells you
2 atoms of hydrogen
and
1 atom of oxygen.
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SUBSCRIPTS
The small numbers after the element’s name.
No subscript means there is only 1 atom present. (The one is not needed.)
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Counting Atoms
1. List the elements.
Cu
S
O
2. Record the atoms of each element.
Cu-1
S-1
O-4
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Multiple Choice
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Multiple Choice
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Multiple Choice
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Multiple Choice
Which elements are in the formula shown above?
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Multiple Choice
Which of the following accurately describes the chemical formula of the molecule shown above?
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Multiple Choice
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Multiple Choice
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Multiple Choice
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Multiple Choice
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Multiple Choice
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Multiple Choice
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Multiple Choice
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Multiple Choice
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Subscripts + Coefficients
Big number at the beginning of this formula is a coefficient.
Represents the number of molecules for that compound
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Subscripts + Coefficients
This formula means there are 2 H2SO4 molecules.
We know in each molecule there are:
2 hydrogens
1 sulfur
4 oxygens
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To find the total number of atoms:
multiply each of these atoms by 2.
2 hydrogens x2
1 sulfur x2
4 oxygens x2
Total atoms for this formula = 14
Chemical Formulas
How are chemical formulas used to identify substances?
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