Covalent bonding occurs between two oxygen atoms to form O2. What's the partial charge on each oxygen atom in 02? A. Both oxygen atoms have positive partial charge.
B. Both oxygen atoms have negative partial charge.
C. Both oxygen atoms have zero partial charge.
D. One oxygen atom has positive partial charge, and the other has negative partial charge.

Both oxygen atoms have zero partial charge.

Explanation:

In covalent bonds, electrons are shared between the two bonding atoms. The shared electron pair of the covalent bond is positioned between the nuclei of the two bonding atoms.

A covalent bond may be formed between two or more elements of different electronegativities. When a difference in electro negativity exists between these atoms in a covalent bond, the molecule becomes polarized. The shared electron pair of the covalent bond becomes closer to the nucleus of the more electronegative atom (s). This more electronegative atom (s) becomes partially negative while the other atom becomes partially positive.

When the two bonding atoms are of equal electronegativities such that the electro negativity difference between the bonding atoms is zero, there is now no difference in electro negativity and no consequent partial charges.

Since the two oxygen atoms have the same electro negativity, there is no difference in electronegativity, hence there is no partial charge between the two oxygen atoms.

altitude, density, pressure

air gets less dense the higher the altitude and also the air pressure is less as altitude rises.

answer: the enthalpy of the overall chemical reaction is +87.88 kj or +88 kj.

according to hess's law, the overall enthalpy of a reaction is the difference between the sum of enthalpy values of all the products and the sum of enthalpy values of all the reactants.

δh(reaction) = ∑nδh(products) - ∑nδh(reactants)

δh(reaction) = [δh +δh] - [δh]

δh(reaction) = [1(-287.02) + 1(0) ] - [1(-374.9)] kj = +87.88 kj

here, δh (pcl3) = -287.02 kj, δh(cl2) = 0, δh(pcl5) = -374.9 kj

therefore, enthalpy of the overall reaction is +87.88 kj or +88 kj.