Ihave a midterm tommorow
1)distinguish between polar compounds and non-polar compounds
2)identify chemical bonds and the different types of bonding

A polar bond is formed with atoms having different electronegativities. The bonding electrons are attracted more towards the atom with greater electronegativity resulting in unequal sharing of electrons. Therefore the molecule develop partial charges and becomes polar. Polar molecules have dipole moment that is the partial charge on molecules due to differences in electronegativity between atoms.

A non-polar bond is formed with atoms having the same electronegativity, hence the bonded pair of electron is shared equally between atoms. Non-polar molecules have no moment.
Note that: symmetrical molecules having polar bonds are non-polar because the dipoles of the bond exert equal and opposite effect. Hence the dipoles cancel the charges.

Example: HCl
In HCl, Cl is more electronegative therefore Cl atom pulls the electron pair of the covalent bond towards itself and develops a partial negative charge. Consequently H develops a partial positive charge. This therfore leads to the formation of a dipole.

Answer:

a. energy is absorbed in the reaction.

explanation:

if in a given reaction the energy of products is greater than the energy of reactants it means that reaction is endothermic and during the reaction, the energy is absorbed by reactants. in an endothermic reaction, the products have more stored chemical energy than the reactants. and in this reaction the reactants are more stable than products before the compounds with less energy are always more stable.

The answer is 4 i don't know if its right let me see.