How many orbitals are there in the shell with n = 4?

16

Explanation:

The number of orbitals can be calculated when energy level is given.

For example:

n = 4

So in 4th energy level number of orbitals are,

n² = 4² = 16

There are 16 orbitals when n=4

One is 4s three are 4P five is 4d and seven are 4f.

while the number of electrons in energy level can be calculated as

2n²

n is energy level.

For n=4

number of electrons are,

2(4)² = 32

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.