# Mathematics and Molecules for K-12 students- A STEM Activity Pt.2

What is the relationship between molecular modeling and mathematics?

PART II

(-- See Part I if this is your first page view.)

Let's begin with the two simple molecules, wate and carbon dioxide.

Rotate and zoom the two molecules (you can rotate the molecules but hold the cursor over the molecule click on left mouse button and rotate . Notice that the three atoms in carbon dioxide (right side) form a linear molecule. That means the angle formed (with carbon as the vertex point is -- put you answer in the space for question 8 and then submit.

Question 8: degrees
Does water form a linear molecule? No, water is a bent molecule.
Question 9: If oxygen is at the vertex what type of angle does the water molecule have (acute, obtuse or right angle)?

We can use Jsmol to find the actual angles formed.

TRY THIS NOW!

 To measure angles Double click on center of first hydrogen atom, then drag the cursor, to the middle oxygen atom, click once, then drag to the second hydrogen atom and click twice.

What is the angle (to the nearest tenth degree) formed in a water molecule?
Question 10: degrees

Now try using Jsmol
to measure the distances!

 To measure distance Label the atoms: Right mouse button -->Labels --> With atom names Double click on hydrogen (H33) then drag to oxygen (O28) -- double click again

What is the distance in angstroms from each carbon to oxygen in the CO2 molecule shown above? Jsmol uses nanometer so you need to convert to Angstroms.

1 nanometer = 10 Angstroms.

Question 11: Angstroms

Question 12: What is the distance in angstroms from each hydrogen to oxygen in the H2O molecule?

Question 13: What is the distance from the tip of one hydrogen in a water molecule to the other hydrogen? (Click first on one hyrogen atom then the other.

If 1 angstrom = 10 -10 meters, approximately how many molecules of would it take to make a line of water 1 centimeter long?