1.25g of gallium reacts with oxygen to give 1.68g of GaxOy. what is the value of x+y
Answers
Answer:
Since you are "allowing" the Ga to react with O2 you can assume that there is an excess of O2. This means that all the Ga will react to form the oxide, so there will be 1.25 g of Ga in the oxide.
The mass of O in the oxide will then be total mass oxide - mass of Gallium
mass O in oxide = 1.68 g - 1.25 g
= 0.43 g O in the oxide.
Now work out how many moles of each atom are in the oxide from the masses
moles = mass / molar mass
molar mass O = 16.00 g/mol
molar mass Ga = 69.72 g/mol
moles Ga = 1.25 g / 69.72 g/mol
= 0.0179 moles
moles O = 0.43 g / 16.00 g/mol
= 0.0269mol
So the molar ratio of Ga to O
is 0.0179 mol to 0.0269 mol
To get this in into its simplest ratio we divide both sides of the ratio by the smallest number
Ga : O
(0.0179 / 0.0179) : (0.0269 / 0.0179)
So
Ga : O
1 : 1.5
Now, to express as whole numbers we need to multiply by an integar that gives us the smallest two whole numbers
If we multiply the ratio by 2 we get
Ga : O
2 : 3
Thus formula is
Ga2O3