Name: _______________________________________________________
Period: ________
Chalk Lab Activity
Introduction – Chalk is a commonly used tool in schools used for instruction.
Chalk is made of a compound named calcium carbonate, which is also the main
component in the shells you can find at the beach and limestone (which is one of
the main types of rocks that make up base of Florida). The formula for calcium
carbonate is CaCO3.
Purpose: To have fun and do some chemistry at the same time.
Objectives:
 Determine the molecular mass for calcium carbonate.
 Determine the number of moles of “chalk” used.
Materials:
Piece of Chalk
Balance
Calculator
Periodic Table
Procedure:
1. Get a piece of chalk, measure its mass on the balance and Record in the Data Table.
2. Go outside (into the hall) and draw something on the ground (cement). STUDENTS THAT
WRITE OR DRAW ON OTHER SURFACES WILL RECEIVE A GRADE OF 0 (ZERO) on the
activity.
3. Go back inside and measure the mass of the chalk and Record in the Data Table.
4. Return all materials to where it belongs and Wash your hands.
5. Perform the Calculations and complete the Analysis and Conclusion questions and turn sheet in by
end of class period.
Data:
Data Table
Initial Mass of Chalk (g)
Final Mass of Chalk (g)
Mass of Chalk Used (g)
Moles of Chalk Used (mol)
Molecules of Chalk Used (molecules)
Atoms Used (atoms)
Calculations:
1. Calculate the mass of Chalk Used. SHOW ALL WORK!!!
2. Calculate the molecular mass for chalk (calcium carbonate). SHOW ALL WORK!!! (Hint: the
chemical formula is in the introduction.)
3. Using the molecular mass found in #2, calculate the number of moles of chalk used. SHOW ALL
WORK!!!
4. Using the number of moles found in #3, calculate how many molecules of chalk (calcium
carbonate) were used. SHOW ALL WORK!!!
5. Using the number of molecules found in #3, calculate how many atoms were used. (Hint –What is
the formula for chalk?) SHOW ALL WORK!!!
6. Calculate the percent mass of each of the elements in chalk. SHOW ALL WORK!
Analysis and Conclusions –
1. A similar compound to chalk, gypsum, is used in the construction of homes as the primary
chemical in dry wall. The chemical formula for gypsum is CaSO4·2H2O. Calculate the number of
moles of gypsum in a 1,500 gram sample.