Question

Aluminum sulfide reacts with water to form aluminum hydroxide and hydrogen sulfide. If 10.6 grams of aluminum hydroxide is produced, how many grams of water were reacted?

Answer 1

There reacts 7.35 grams of H2O

Step-by-step explanation:

Step 1: Data given

Mass of aluminium hydroxide = 10.6 grams

Step 2: The balanced equation

Al2S3(s) + 6H2O(l) → 2Al(OH)3(s) + 3H2S(g)

Step 3: Calculate number of moles Al(OH)3

Moles Al(OH)3 = mass Al(OH)3 / molar mass Al(OH)3

Moles Al(OH)3 = 10.6 grams / 78.00 g/mol

Moles Al(OH)3 = 0.136 moles

Step 4: Calculate moles of H2O

For 1 mol of Al2S3 we need 6 moles of H2O to produce 2 moles of Al(OH)3 and 3 moles of H2S

For 0.136 moles of Al(OH)3 we need 3*0.136 = 0.408 moles of H2O

Step 5: Calculate mass of H2O

Mass H2O = moles H2O * molar mass of H2O

Mass H2O = 0.408 * 18.02 = 7.35 grams

There reacts 7.35 grams of H2O