Name _______________________________
Zn(solid) + HCl(liquid) 
ZnCl2 (aqueous) + H2(gas)
In this lab you will be given a piece of zinc metal. You will use the mass of zinc and the balanced equation
to predict the mass of zinc chloride that should be produced if all the zinc reacts with hydrochloric acid.
You will then do the actual reaction in the lab to see how close your calculated prediction (theoretical
yield) is to the actual mass of zinc chloride produced (actual yield).
1. Balance the above equation!
2. Mass a piece of zinc metal and record its mass in the data table.
3. Calculate the theoretical mass of zinc chloride that should be produced if your piece of zinc were to
completely react with hydrochloric acid. Show your calculations here!
Theoretical yield = ___________ grams of ZnCl2
4. Mass a clean, dry Erlenmyer flask and record its mass.
5. Place your piece of zinc in the flask and add about 5 ml of hydrochloric acid. (You can always add more
if needed.)
6. Record your observations. (Feel the bottom of the flask.)
7. The zinc metal should disappear when it has completely reacted. You won’t see the zinc chloride
because it is dissolved in the acid.
8. Place the flask on a hot plate in the fume hood to boil away the excess acid.
9. When the liquid is gone, use tongs to carefully remove the flask from the hot plate. Allow to cool
before placing on the balance. The crusty stuff is the zinc chloride.
Mass of zinc metal
Mass of clean, dry, empty flask
Observations during the reaction
Mass of flask + zinc chloride
Mass of zinc chloride
10. Was the actual mass of zinc chloride higher or lower compared to the theoretical mass of zinc
chloride?
11. What could account for the difference between the actual and theoretical mass of zinc chloride?