Build a Molecule Webquest
Name ___________________________
7th Grade PSI
Score: ___________________ / 10
Objectives:
Students will be able to:


Construct models of molecules using chemical formulas.
Display the knowledge that a coefficient tells you how many individual molecules
there will be.
Materials Needed:

Computers with Internet access
Background Information:
Molecules are pure substances that are made up of two or more atoms chemically
bonded together. When two different elements bond together, they do not keep their
physical properties. Compounds have physical properties that are entirely unique.
Sodium (left) and Chlorine (a gas, center) bond together to form Salt (right).
Molecules are represented by a chemical formula which tells you the proportion of
elements that make up the substance. The chemical formula tells you what types of
elements make up the molecule and how many atoms of each element are included. A
subscript that follows each element tells how many atoms are required. If there is no
subscript following an element, then that means that there is 1 atom of that element.
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7th Grade PSI
Matter and Its Properties
When there is more than one of the same molecule present, we call the substance a
compound. When you fill a bottle of water, billions of water molecules are present.
When you want to express that more than one molecule is present, a coefficient is
added to the chemical formula. The coefficient goes before the chemical formula and
tells you how many molecules there are. (If there is no coefficient, then there is only 1
molecule present.)
Procedure
1) Go to www.google.com and type in: phet Build a Molecule
2) Click on the 1st link
(Direct link for this website: http://phet.colorado.edu/en/simulation/build-amolecule)
3) Click:
Upon clicking this, you will be taken to the following program:
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7th Grade PSI
Matter and Its Properties
4) Build all of the molecules in Collection 1. Be sure to use all available kits at the
bottom of the screen.
5) Notice the varying sizes of the atoms. What do you think is true about an atom
such as Oxygen compared to an atom such as Hydrogen?
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6) Choose one of the molecules from Collection 1 and draw it below:
Name of the molecule:
____________________________________________________________
This molecule is made of _______________ (#) atoms of
_____________________________ (element name).
It is also made of __________________________ (#) atoms of
_____________________________________ (element name). (Optional based
on your choice)
7) When you have finished Collection 1, move on to Collections 2-4. (The rest can
be completed later if you have time.)
8) Click on
at the top of the screen.
9) Before starting, answer the questions below:
a. What elements are needed to create CO2 (and how many of each)?
_______________________________
_______________________________
b. How many CO2 molecules are needed to make 2CO2?
________________________
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7th Grade PSI
Matter and Its Properties
c. How many total Carbon atoms are needed to make 2CO2?
_____________________
d. How many total Oxygen atoms are needed to make 2CO2?
_____________________
e. What is the name of CO2?
__________________________________________________________
f. Create the 2CO2 compound.
10) Create the rest of Collection 1 as well as Collection 2.
11) Click on
at the top of the screen.
12) Find the kit that will allow you to create H2POH. What is the name of this
molecule?
________________________________________________________________
13) Use the remaining kits to create another molecule.
a. What is the name of the molecule made?
___________________________________________________________
b. What would be the chemical formula for this molecule?
___________________________________________________________
c. Draw the molecule below:
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7th Grade PSI
Matter and Its Properties