A 4.78-g sample of aluminum completely reacts with oxygen to form 6.67 g of aluminum oxide. What is the mass percent composition of aluminum in aluminum oxide?
1 Answer
Oct 30, 2015
Explanation:
The percent composition of aluminium in the
resulting oxide will be the ratio between the mass of aluminijm and the total mass of the oxide, multiplied
by
#"% Al" = m_"Al"/m_"oxide" xx 100#
In your case, you know that a
unknown aluminium oxide.
Moreover, you know that this oxide has a mass of
Since all the luminium that initially reacted with the oxygen is now a part of the oxide, you can say that its
percent composition in the oxide will be
#"% Al" = (4.78color(red)(cancel(color(black)("g"))))/(6.67color(red)(cancel(color(black)("g")))) xx 100 = 71.664%#
Rounded to three sig figs, the
answer will be
#"% Al" = color(green)(71.7%)#
