Compound*
Matter that is made up of two or more
elements (atoms) chemically combined
and cannot be separated by physical
means.
*Molecule
The molecule is the smallest unit of a
compound.
Analogy
atom is to…
element
as
molecule is to…
compound
What do we mean by
“chemically combine or bond”?
PP
sodium (Na)
PP
+
chlorine Cl = NaCl
What do we mean by
“chemically combine or bond”?
-
-
-
-
-
-
11
P
PP11 P
12
-
-
-
-
17
P
PP11 P
18
-
-
-
-
-
-
-
-
-
sodium (Na)
+
chlorine (Cl) = NaCl
Sodium and Chlorine
http://jchemed.chem.wisc.edu/JCESoft/CCA/samples/cca3NaCl.html
http://www.seilnacht.com/film/english.html
Compound Facts
• The elements that make up a compound
lose their properties.
• A compound has different properties
than the elements that make it up.
• Energy is always used when a compound
is broken up or put together.
• It takes another chemical reaction to
separate a compound.
Compound Facts Continued
• The ratio of the elements that make
up a compound are always the same
for that compound.
• Example: water is always two
hydrogen atoms and one oxygen
atom.
H2O vs H2O2
CO2 vs CO
Parts of a compound
Chemical Formula Chemical Name
5CO2 = carbon dioxide
subscript (how many atoms are present)*
coefficient
*When there is no subscript written, it is assumed that
the subscript is 1
What is the chemical name for the
following compounds?
1. H2O
water
2. NaCl
salt (sodium chloride)
3.CaCO3
calcium carbonate
4. CO2
carbon dioxide
5. SiO2
silicon dioxide
6. C12H22O11
sugar
True or False:
False 1. Compounds are made up of only one type of
atom.
False 2. Compounds can be found on the periodic table.
False 3. Subscripts are used in compounds to determine
the number of elements in the compound.
False 4. You can separate a compound by a physical
change.
True 5. It takes a chemical change to form a compound.
False 6. The proportions of the elements that make up a
compound can change and you would still have the
same compound.
Examples:H20 (water) vs H2O2(hydrogen peroxide)
CO2 (carbon dioxide) vs CO (carbon monoxide)
Venn Diagram- (homework)
Three in each box.
Elements
Compounds
Bell Ringer A day 11/10, B day 11/11
No Bell Ringer Quiz – study
1. One partner get a TTB scale and
put it on your desk.
2. One partner get
safety equipment
for you and
your partner.
1. Please get out your
homework ws#5.
Elements
Broken down
by nuclear
changes
only; made of
only one atom
Compounds
Pure
Substance
Matter; made of
atoms; man
made or natural
Solid, liquid, gas
Does not break
Down by
Chem. changes
Chemical
changes form
and break down
compounds
Made up
of more than
one atom
Physical changes
form and break
mixtures down
Not a pure substance
Mixtures