part 6 MW2 Flashcards
What is the meant by the term “electronegativity” ?
Eletronegativity is the power / ability of the atom in the molecules to attract bonding electrons toward itself on a chemicial bond.
Explain why ice float on water.
The attraction between water molecules is predonminantly hydrogen bond. Hydrogen bond is directional. In ice, the H2O molecules have a tetrahedral arrangement / are packed in open structure so the volume increases. In liquid water, the H2O molecules have relative motion and this leads to the collapse of the open structure. The molecules become more closely packed so liquid water has a higher density than ice.
What is the octet rule ?
Octet rule state that all atoms tend to attain the stable elecronic configuration of a noble gas by sharing or transfer of electrons.
Identify, with explaination, the polar bond(s) in CH2Cl2
C–H and C–Cl bonds are polar. C and H have different elecronegativities.
Explain whether SF6 is a polar molecule.
No, because SF6 molecules is symmetrical, the polarites of the S–F bonds in SF6 cancel out.
A negataively charged rod is brought near the jet of water running out from a burette. Explain why the jet of water was deflected with the reference to the structure of water.
The structure of water is non-linear. The dipole moments on the two O-H bonds cannot cancel each other / water has a net dipole mement / water is a polar molecule. Therefore it would be attracted by the eletric field.
Describe and explain the formation of hydrogen bonding between water molecules.
Hydrogen bonding forms between the H atom of a H2O molecule and the lone pair electron of O atom of another H2O molecule. O is a highly electronegative element on comparing with H.
Suggest whether ethane-1,2-diol is soluble in water.
It is soluble in water because it has a small molecular size and the hydroxyl groups in it can form hydrogen bonds with water.
