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?

There reacts 7.35 grams of H2O

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