Question

If .29 g of aluminum reacts with excess sulfur, what mass of aluminum sulfide can form?

Answer 1

To start with, Aluminium sulfide is Al\(_2\)S\(_3\)

Answer 2

2Al + 3S ---> Al2S3

first find mole of Al because you are given mass of Al
mole= mass/Molecular mass
Molecular mass of 2Al you can find from periodic table (do consider the coefficient, its 2 that means there are 2 Al atoms)
and get the mole

next
look at the ratio
between Al and Al2S3
(look at coefficients)
you can see that its 2:1
that means
2--- the mole you just got
1 ---- X mole of Al2S3

so find X= mole that you just got/ 2

now you have the mole
use formula
mole= mass/ Molecular mass

and calculate for mass

mass= mole * Molecular mass

mole - you just got it
Molecular mass of Al2S3 you can find from periodic table

Hope it helps :)