Astudent in lab prepared a cereal sample solution for spectroscopic analysis as described in the lab manual, and found the concentration of fe3+ in the sample to be 2.50 x 10−5 m. if her sample solution was prepared by diluting 25 ml of the original solution to a total volume of 100 ml, what is the concentration of the original solution?

A student in the lab prepared a cereal sample solution for spectroscopic analysis as described in the lab manual, and found the concentration of Fe3+ in the sample to be 2.50 x 10−5 M. The concentration of the original solution is 1.00 × 10⁻⁴ M.

The concentration of a solution is the estimate of how much solute has been dissolved in the solvent.

The molar concentration of Fe3+ =  2.50 × 10⁻⁵ M

∴

In 1 liter, there are 2.50 × 10⁻⁵ M  of Fe3+

Now in 100 mL which is equivalent to 0.1 L, the concentration of Fe3+ will be:

= 2.5 × 10⁻⁶ M

Since the total volume of the solution is 100 mL, the 2.5  × 10⁻⁵ M is also present in 25 mL of the stock(original) solution.

∴

= 1.00 × 10⁻⁴ M concentration of the original solution

Therefore, we can conclude that the concentration of the original solution is 1.00 × 10⁻⁴ M.

Learn more about the concentration of a solution here:

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The concentration of the original solution is 1x10*-4 M

Explanation:

[Fe3+} = 2.50 x 10−5 M

It means that in 1 L, I have 2,50 x 10−5 moles of cation.

These are the rules of three involved.

1 L 2,50 x 10−5 moles

0,1 L (0,1 L . 2,50 x 10−5 m) / 1L = 2,50 x 10−6 moles

As the total volume of solution is 100 ml, the 2,50 x 10−6 moles are also in 25 ml of the stock solution.

So:

0,025 L 2,50 x 10−6 moles

1 L (1L . 2,50 x 10−6 m) / 0,025 L = 1x10*-4 M

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.