Changes or transforms chemicals into other chemicals Ex Iron Oxygen Iron Oxide rust Physical Science Review What is the product What are the reactants Chemical formula shows the kind and proportion of atoms of each element that occurs in a particular compound ID: 913967
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Slide1
Chemical Reactions
Slide2What is a chemical reaction?
Changes or transforms chemicals into
other
chemicalsEx: Iron + Oxygen Iron Oxide (rust)Physical Science ReviewWhat is the product?What are the reactants?
Slide3Chemical formula
shows the kind and proportion of atoms of each element that occurs in a particular compound
Slide4Molecules
are the simplest part of a substance that retains all of the properties of the substance and exists in a free state
Some molecules are
large and complex
Slide5Chemical Formulas
Subscript
after a symbol tell the number of atoms of each element.
H
20 has 2 atoms of hydrogen & 1 atom of oxygen.
Slide6Chemical Formulas
Coefficients
before a formula tell the number of molecules.
3O2
represents 3 molecules of oxygen or (3x2) or 6 atoms of oxygen.
Slide7The
physical and chemical properties
of a compound differ from the physical and chemical properties of the individual elements that compose it
Slide8Most atoms are not stable in their natural state
They
tend to react
(combine) with other atoms in order to become more stable (undergo chemical reactions)
In
chemical reactions
bonds are broken; atoms rearranged and new chemical bonds are formed that store
energy
Slide9Energy and Chemical Reactions
Living things undergo
thousands of chemical reactions
as part of the life process
Slide10Many are very complex involving
multistep
sequences called
biochemical pathwaysChemical equations
represent chemical reactionsReactants are shown on the left side
of the equation
Products
are shown on
the right side
Slide11The number of each kind of atom must be the same on either side of the arrow
(equation must be balanced)
Bonds
may be broken or made forming new compounds