gs The composition of a gas mixture is 20% O2, 20% N2 and 60% He by mass analysis. What is the molar mass of this mixture

Explanation:

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In this case, since the molar mass of a gas mixture can be computed as a weighted average containing mole fractions:

Now, since we are given the by mass percent of each gas, by assuming 1 g of mixture, we therefore have 0.20 g of oxygen, 0.2 g of nitrogen and 0.6 g of helium; next we compute the moles of each gas:

Next, we compute the mole fractions:

Now, we compute the molar mass of the mixture as follows:

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the electronic configuration of an atom with eight electrons is 1s²2s²2p⁴. the orbital diagrams are shown in the figure.

as per the hunds rule:

1. electrons tend to avoid being in the same orbital as per as practicable.

2. electrons in different orbitals of the same energy will have their spin parallel.

this can be illustrated from the multiplicity of the orbitals of the atom. as there are four electrons in the p orbital and p orbital has 3 sub-shells. the electrons can be fed in different ways as shown in the figure but the correct orbital diagram will be as per the hunds rule.