How many moles of aluminum is needed to form 3.4 moles of aluminum oxide?
3.4 mol Al2O3 x (2 mol Al/1 mol Al2O3) = ?? mol Al.
Note how the units we don't want cancel but the unit we want to keep remains.
To calculate the number of moles of aluminum needed to form 3.4 moles of aluminum oxide, we can use the mole ratio between aluminum and aluminum oxide.
From the balanced chemical equation of the reaction, we know that 2 moles of aluminum (Al) are needed to form 1 mole of aluminum oxide (Al2O3).
So, to find the number of moles of aluminum (Al) needed, we can set up a ratio:
3.4 mol Al2O3 / 1 mol Al2O3 * (2 mol Al / 1 mol Al2O3) = 6.8 mol Al
By multiplying the given quantity (3.4 mol Al2O3) by the appropriate mole ratio (2 mol Al / 1 mol Al2O3), we can cancel out the units we don't want (mol Al2O3) and keep the unit we want (mol Al), giving us the result of 6.8 moles of aluminum (Al) needed to form 3.4 moles of aluminum oxide (Al2O3).