1. some areas where earthquakes and volcanic activity often occur together are along oceanic ridges where lithospheric plates move apart. if we know the age of the crust and the distance from the ridge center, we can calculate how fast the two plates are moving away from each other. look at the figures of oceanic ridges (spreading centers) a. calculate the half-spreading rate across the mid-atlantic ridge and east pacific rise. this is the rate at which one of the plates is growing.

b. determine the full spreading rate for these same ridges. this is the rate at which the ocean basins are opening

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.

the number of valence electrons for each molecule or ion is shown beneath the structure. remember hydrogen will not have more than two electrons. this hydrogen is part of a covalent bond (sharing two electrons). a double bond here would cause hydrogen to share four electrons with phosphorus.

the solar system used to have much dust particles option no d