The balanced equation shows the reaction between aluminium hydroxide and hydrochloric acid to form aluminium chloride and water: Al(OH)3 + 3HCl = AlCl3 + 3H2O. 1 mole of aluminium chloride was formed, what mass of aluminium hydroxide was formed?

1 Answer
Jul 9, 2017

Answer:

#80# #"g Al(OH)"_3# (one sig fig)

Explanation:

I'll assume you mean what mass of aluminum hydroxide reacted.

We can use the coefficients of the equation to determine the number of moles of #"Al(OH)"_3# that react, knowing that #1# #"mol AlCl"_3# forms:

#1cancel("mol AlCl"_3)((1color(white)(l)"mol Al(OH)"_3)/(1cancel("mol AlCl"_3))) = 1# #"mol Al(OH)"_3#

which makes sense given their molar ratio is #1:1#.

Now, we can use the molar mass of aluminum hydroxide (#78.00# #"g/mol"#) to calculate the number of grams that react:

#1cancel("mol Al(OH)"_3)((78.00color(white)(l)"g Al(OH)"_3)/(1cancel("mol Al(OH)"_3))) = color(red)(80# #color(red)("g Al(OH)"_3#

which I suppose will round to #1# significant figure, the amount given in the problem..