Home > categories > Minerals & Metallurgy > Aluminum Foils > Stoichiometry??? Help?!?
Question:

Stoichiometry??? Help?!?

This equation shows the formation of aluminum oxide, which is found on the surface of aluminum objects exposed to the air4Al(s) + 3O2(g) 2Al2O3(s)a.) Write the six mole ratios that can be derived from this equation.b.) How many moles of aluminum are needed to form 3.7mol Al2O3?Please help! I don't even know where to beingStep-by-step instructions would be greatly appreciated and given 5 stars!

Answer:

a.) This part is asking how you can compare the elements/molecules in the given equationIn this case you can compare aluminum to oxygen, aluminum to aluminum oxide and oxygen to aluminum oxidePlus you can reverse all your comparisons too1.) 4Al / 3O2 2.) 3O2 / 4Al 3.) 4Al / 2Al2O3 4.) 2Al2O3 / 4Al 5.) 3O2 / 2Al2O3 6.) 2Al2O3 / 3O2 bNow you have to set up an equation using the correct ratioWhat is your given? (3.7mol Al2O3) What do you need to find? (mol of Al) Which ratio has those two? (4Al / 2Al2O3 and 2Al2O3 / 4Al) So how do you know which to use? It all has to do with how units cancelA unit in the denominator will cancel a unit in the numeratorThe uncanceled unit will be in the answerSo you'll need 4Al / 2Al2O3 as your ratioHere's the equation: Given ratio answer 3.7 mol Al2O3 (4 mol Al / 2 mol Al2O3) 7.4 mol Al The parentheses don't have any purpose in the equation except to help you see the ratioMoles of Al2O3 cancel out leaving moles of Al for the unitsDon't forget to label all your units when you write out problemsFirst, science teachers are real sticklers for labelingSecond, if your units come out funky, it's a clue to recheck how you set up a problem.

Share to: