How many formula units are present in a $12.6*g$ mass of $MgCl_2$ ?

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Answer 1 · 2017-06-17T17:01:52

Approx. $8xx10^22$ $"formula units............"$

We find the molar quantity by dividing the mass of substance by the molar mass.....

$(12.6*g)/(95.21*g*mol^-1)=0.132*mol$

How did I get the $95.21*g*mol^-1$ number?

And this there are $0.132*mol$ $Mg$ , and $2xx0.132$ $Cl$ atoms....

But a mole is SIMPLY A NUMBER, i.e. $N_A=6.022xx10^23*mol^-1$ .

And so the number of formula units.........

$6.022xx10^23*mol^-1xx0.132*mol=7.97xx10^22$ formula units.

How many magnesium atoms, and how many chlorine atoms?

How many formula units are present in a 12.6*g12.6*g mass of MgCl_2MgCl_2?