The question is incomplete, here is the complete question.
When a mixture of sulfur and metallic silver is heated, silver sulfide is produced. What mass of silver sulfide is produced from a mixture of 3.0g Ag and 3.0g
.
Answer : The mass of silver sulfide is produced from a mixture is 3.44 grams.
Explanation : Given,
Mass of Ag = 3.0 g
Mass of
= 3.0 g
Molar mass of Ag = 107.8 g/mole
Molar mass of
= 256 g/mole
Molar mass of
= 247.8 g/mole
First we have to calculate the moles of Ag and
.


Now we have to calculate the limiting and excess reagent.
The balanced chemical reaction is,

From the balanced reaction we conclude that
As, 16 mole of
react with 1 mole of 
So, 0.0278 moles of
react with
moles of 
From this we conclude that,
is an excess reagent because the given moles are greater than the required moles and
is a limiting reagent and it limits the formation of product.
Now we have to calculate the moles of 
From the reaction, we conclude that
As, 16 mole of
react to give 8 mole of 
So, 0.0278 moles of
react to give
moles of 
Now we have to calculate the mass of 


Therefore, the mass of silver sulfide is produced from a mixture is 3.44 grams.