Question

1.) What is the molecular weight of the ketone shown below?

2.)Dry ice sublimes at −78.5 oC at a pressure of 1 atm. At room temperature and 1 atm pressure, what is happening to the dry ice molecules on a molecular level as sublimation occurs?



3.)For the pairs of molecules given below, list the intermolecular forces in each molecule. Also, give the types of electrostatic interactions that could occur between each pair of molecules



cyclohexane and CH2Cl2


CH3CH2OCH2CH3 and CH3CN

Answer 1

See explanation

Step-by-step explanation:

1. The Ketone was not sown in the question but i can give you a general idea of how to calculate its molecular weight. A ketone has a general molecular formula of CnH₂nO.

The molecular weight is calculated knowing that the relative atomic mass of carbon is 12, that of hydrogen is 1 while that of oxygen is 16.

Hence from the general molecular formula, the molecular weight of any ketone is calculated from; n(12) + 2n(1) + 16. Where n represents the number of atoms of each element in the ketone.

2. Sublimation of dry ice occurs when the molecules in dry ice absorb sufficient energy in the form of heat such that they now have enough energy for some molecules to overcome the inter molecular forces acting in the solid crystal and transform directly into the vapor phase. This process is endothermic.

3.

cyclohexane and CH2Cl2 molecules are held together by dispersion forces.

CH3CH2OCH2CH3 and CH3CN are polar molecules held together by dipole-dipole forces.