When m2s3(s) is heated in air, it is converted to mo2(s). a 3.280 g sample of m2s3(s) shows a decrease in mass of 0.228 g when it is heated in air. what is the average atomic mass of m?

The average atomic mass of M is 181.33 g/mol.

Explanation:

First off we need to know the reaction that takes place. The balanced reaction of M₂S₃(s) is:

The important section for this problem is this:

**Thus, the number of moles of M in M₂S₃ is equal to the number of moles of M in 2MO₂.

The decrease in mass means that M₂S₃ reacted and produced MO₂, thus the mass of MO₂ is 3.280-0.228=3.052 g

Now let's say x is the atomic weight of M, and write the molecular weights (Mw) of those two compounds:

Mw of M₂S₃= 2x + 96 g/mol

Mw of MO₂= x + 32 g/mol

Now we determine the moles of each compound, using the formula [ moles = mass / molecular weight ]:

Moles of M₂S₃=

Moles of MO₂=  

Using the equivalence marked by asterisks, we're left with (note that the second denominator is multiplied by 2 because of the reaction coefficients):

We solve for x:

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Thus, the average atomic mass of M is 181.33 g/mol.

"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."

am i too late?

explanation: