Question

7.02 x 10^23 molecules of X2, a ssubstance consisting of diatomic molecules, has a mass of 296 grams. Determine the atomic weight (mass of a mole of atoms) of element X.
a. 254 g/mol.
b. 296 g/mol.
c. 148 g/mol.
d. 127 g/mol.
e. 507 g/mol.

Answer 1

Answer:

d. 127 g/mol.

Explanation:

Hello!

In this case, since we have the amount of molecules of this this compound, we are able to compute the moles out there by using the Avogadro's number:

$mol=7.02x10^{23}molec*\frac{1mol}{6.022x10^{23}molec}=1.17mol$

Which correspond to the moles of X2. Then, by using the mass we are able to compute the molar mass of X2:

$MM=\frac{296g}{1.17mol}\\\\MM=254g/mol$

It means that the atomic mass of X halves the molar mass of X2, which is then d. 127 g/mol.

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