Propane has three atoms
of carbon and eight
atoms of hydrogen.
What is propane's
chemical formula?
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C3H8
List the elements in this
compound: H2SO4
How many atoms of each
element are in the compound?
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H2SO4
Hydrogen – 2 atoms
Sulfur – 1 atom
Oxygen – 4 atoms
What does a
chemical equation
tell us?
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Chemical equations tell us how
many atoms or molecules react
with each other and how much
of a substance is needed to
react properly with another.
A student wrote the following
equation:
4Al + 3O2 2Al2O3
– Write a sentence to describe
what occurs in this reaction.
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In this reaction, aluminum reacts
with oxygen to form Al2O3.
What do coefficients &
subscripts show us in
chemical formulas?
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Coefficients – the number of
molecules
Subscripts – the number of atoms
H2SO4 =
subscript
2 – hydrogen
No number is understood to be “1”
1 – Sulfur
4 – Oxygen
coefficient
3H2SO4 =
H2SO4
H2SO4
H2SO4
6 – H, 3 – S, 12 - 9
Identify the reactants, products, subscripts,
and coefficients in this chemical equation:
6 CO2 + 6 H2O + light → C6H12O6 + 6 O2
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6 CO2 + 6 H2O + light → C6H12O6 + 6 O2
Coefficients
Subscripts
Carbon Dioxide + Water + Light energy → Glucose + Oxygen
Reactants:
CO2
H2O
light
Products:
C6H12O6
O2