Rotational KE of Cl2 Molecule: Calc Molar Mass 70.0 g/mol

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The discussion focuses on calculating the rotational kinetic energy of a chlorine (Cl2) molecule with a molar mass of 70.0 g/mol. The participants clarify that the moment of inertia (I) should be calculated using the formula I = m * r^2, where r is the distance between the two chlorine atoms, approximately 2.00x10^-10 m. The correct mass of one Cl2 molecule is determined to be 1.16x10^-22 g, derived from the molar mass and Avogadro's number. The rotational kinetic energy is then calculated using the formula KE = 1/2 * I * (angular speed)^2, with the angular speed given as 1.40x10^12 rad/s.

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In a crude model of a rotating diatomic molecule of chlorine (Cl2), the two Cl atoms are 2.00x10^-10 m apart and rotate about their center of mass with angular speed = 1.40x10^12 rad/s. What is the rotational kinetic energy of one molecule of Cl2, which has a molar mass of 70.0 g/mol?

I have tried this problem but I really don't even know where to start..
 
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What is the formula for Rotational Kinetic energy of a an object?
 
KE=1/2* I* (angular speed)^2

I=1/12*m*L^2

would mass=140 g?
 
Why have you chosen I = 1/12* m*l^2? Are you approximating this as a rod of length L? I don't think that's a good idea because most of the mass is concentrated in the atom, not the bond. So I think taking this as two sepearate Cl atoms rotating about the COM is a better idea

Also, the mass will not be 140g. The mass of 1 mol of Cl2 is 70 grams. And you know 1 mol of Cl2 contains around 6.023*10^23 molecules. So what is the mass of 1 molecule?
 
ok i got the mass of one to be 1.16E-22

But then what equation for moment of inertia would I use?
 

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