Answer:
a) 1.2g of arsenic b) 0.64g of arsenic c) 3.481g of gallium d) 3.806g of gallium e) 2.61g arsenic
Explanation:
The balanced equation is:
Ga + As = GaAs, 1:1 mole ratio
a) mass (gallium)/ molar mass of Ga = 4/ 69.723 = 0.0574mol
Mass (arsenic)/ molar mass of As = 5.5/74.9216 = 0.0734, subtracting the moles from each other (knowing already that the ratio is 1:1), arsenic is in excess by 1.2g
b) repeating the procedure (changing the values)
It will be 0.0574 to 0.06593
Arsenic is in excess by 0.00854
0.00854* mass of arsenic (such must be done for the first remaining mole) = 0.64g
c) the mole ratio is 0.0574: 0.00747
Gallium is in excess by 0.05
Mass of excess gallium = 0.05* 69.723 = 3.481g
d) using the mass given, the new ratio is
0.128: 0.0734
Gallium is in excess by 0.054mol
Mass of excess gallium = 0.054*69.723 = 3.806g
e) using the mass again, the new ratio is 0.0574: 0.02,
Gallium is in excess by 0.0374*69.723 = 2.61g
