posted by confused student.. on .
When 21.29 g of element A react completely with 58.37 g of E, compound A2E is formed. When 5.41 g of A react with 32.36 g of G, compound AG is formed. If elements E and G react to form EG3, what mass in grams of G is required to react with 11.94 g of E?
The molar mass of E is 51.413 g mol-1.
how do i start?? i got all the equations lined up, but i don't know where to go from there...
Start with the first reaction. Balance the reaction, you know how many moles of E were reacted, so you then know how many moles of A there are, and the mol mass of A can be figured. Be certain to balance the reaction.
Now, knowing the mol mass of A, go to the second reaction, and figure out how many moles of G reacted, and the mol mass of g
You know the molar mass E = 51.413 from the problem. Therefore, mols element A were 21.29/51.413 = 0.4141 mols A.
Convert that to element E.
mols E = mols A x (1 mol E/2 mols A) = (1/2)*0.4141 = 0.20705.
Convert that to molar mass knowing that 0.20705 mols = 58.37 g. We know #mols = g/molar mass so molar mass E = g/#mols = 58.37/0.20705 = 281.9 if I didn't make a math error.
That should get you started. Post your work if you need more help.