Answer:
The amount of excess is 5.16 grams. Option B is correct
Explanation:
Step 1: Data given
Mass of Zinc (Zn) = 50.0 grams
Mass of Hydrogen chloride (HCl) = 50.0 grams
atomic mass Zn = 65.38 g/mol
Molar mass HCl = 36.46 g/mol
Step 2: The balanced equation
Zn + 2HCl → ZnCl2 + H2
step 3: Calculate moles
Moles = mass / molar mass
Moles Zn = 50.0 grams / 65.38 g/mol
Moles Zn = 0.764 moles
Moles HCl = 50.0 grams / 36.46 g/mol
Moles HCl = 1.37 moles
Step 4: Calculate limiting reactant
For 1 mol n we need 2 moles HCl to produce 1 mol ZnCl2 and 1 mol H2
HCl is the limiting reactant. It will completely be consumed (1.37 moles)
Zn is in excess. There will react 1.37/2 = 0.685 moles
There will remain 0.764 -0.685 = 0.079 moles
Step 5: Calculate the remaining mass of zinc
Mass = moles * molar mass
Mass Zinc = 0.079 moles *65.38 g/mol
Mass Zinc = 5.16 grams
The amount of excess is 5.16 grams. Option B is correct
