If 3.011 x 1023 molecules have a mass of 20.04 grams, what is the molar mass of this substance?

The molar mass of the substance will be 40.08 g.

Explanation:

It is given that molecules of any substance has a mass of 20.04 g.

Now, the number of moles of a substance can be calculated as,

The value of Avogadro's number is .

So, the number of moles of the substance will be,

Now, the molar mass of the substance will be,

Therefore, the molar mass of the substance will be 40.08 g.

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"among the transition metal elements, manganese and zinc have a slight lowering of electronegativities. the reason behind this is that the nuclear charges of these elements are slightly weaker than the other transition metal elements due to the way their valence electrons are filled up. both manganese and zinc have their valence electrons filled up to the 4th shell with 1 pair of electrons (4s2) completely occupying it. although the electrons in the 3rd shell (3d) are yet to be paired since the outer most shell is filled up, the ability of the nucleus to attract electrons is lessened. hence,   the electronegativity (or the ability to attract electrons) is lessened."