# Distance between two atoms

1. Oct 23, 2008

### Naldo6

The distance between a carbon atom (m = 12.0u) and an oxygen atom (m = 16.0u) in the CO molecule is 1.13×10-10 m. How far from the carbon atom is the center of mass of the molecule?

I know i have to found out the CM,

but the center of mas is cm= (r1m1 + r2m2)/(m1+m2)

and i dont have the radios of the twoatoms.... how could i do that?

2. Oct 23, 2008

### Dick

Look up your cm formula. The r1 and r2 are not the radii of the atoms. What are they?

3. Oct 23, 2008

### Naldo6

ok, i mean the position of the atoms, but there the exercise doesnt told me the psoition...

4. Oct 23, 2008

### Dick

It told you the distance between the atoms. Put the origin of your coordinate system anywhere you want. Write down the position of the atoms in that coordinate system and find the coordinate of the center of mass. Then figure out how far it is from the carbon atom.

5. Oct 23, 2008

### Naldo6

ty... i figure out the coordinates system in the origin of one atom and calculate the CM since that point an gets the corrects anwer... ty a lot... can u help me with other problems a posted in a new topic?..

6. Oct 23, 2008

### Dick

Sure. Maybe not tonite. It's late. Other people can help you too.