Aleksza/Soltis
Chemistry
2012-13
Can You Find the Mole Ratio?
(Adapted from GPB Lab Episode 801)
Name:____________________________________MOD:___________
Lab Partners:_____________________________________________
Background:
In this experiment, baking soda (NaHCO3) reacts with hydrochloric acid
(HCl) to produce sodium chloride (NaCl), carbon dioxide (CO2), and water
(H2O). You will determine the moles of reactant used and moles of product
produced using both the lab data and stoichiometry and compare the two.
Materials:
test tube, test tube holder, scoopula, baking soda, 1M HCl, pipette, Bunsen
burner, burner tubing, matches, heat mitt, balance
Safety:
Goggles must be worn during this activity. Long hair and loose clothing must
be tied back. HCl will burn your skin. HOT GLASS LOOKS LIKE COLD
GLASS! Wash your hands after this activity.
Procedures: CHECK OFF ALL STEPS WHEN COMPLETED FOR FULL
CREDIT!
___1. Mass the empty test tube and write your results in the data table on
Line 2.
___2. Add the baking soda to the test tube just to fill the bottom of the
tube.
___3. Mass the test tube with the baking soda and write your results in the
data table on Line1.
___4. Calculate the mass of the baking soda by subtracting the mass of the
empty test tube from the mass of the test tube and baking soda. Enter your
results in the data table on Line 3.
___5.Add a drop of HCl to the test tube and slightly shake the test tube.
Write your observations on the space provided for observations.
___6.Continue to add drops of HCl until the reaction appears to be stopped.
Properly light the Bunsen burner. Heat the solution on the Bunsen burner
until all the liquid is evaporated. Place the test tube on a hot mitt to cool.
TURN OFF the Bunsen burner.
___7.When the test tube is cool find the mass of the test tube plus the
Sodium Chloride. Enter your results in the data table on Line 4.
___8. Enter the original mass of the empty test tube on Line 5.
___9. Calculate the mass of the Sodium Chloride by subtracting the mass of
the empty test tube from the mass of the test tube plus the salt.
___10. Clean up your lab stations.
Data Table:
Line 1
mass of test tube and baking soda
Line 2
mass of empty test tube
Line 3
MASS OF BAKING SODA
Line 4
mass of test tube and sodium chloride
Line 5
mass of empty test tube
Line 6
MASS OF SODIUM CHLORIDE
Reaction Observations:
Conclusion Questions:
1. Calculate the number of moles of baking soda (NaHCO3) used in the lab.
1A. What is the atomic mass of Na:________________
1B. What is the atomic mass of H:_________________
1C. What is the atomic mass of C:_________________
1D. What is the atomic mass of O:_________________
1E. What is the FORMULA weight of NaHCO3:_______________
1F. What is the mass of the NaHCO3 from the lab:_____________
1G. Calculate the moles of baking soda used:
2. Calculate the number of moles of sodium chloride (NaCl) produced in the lab.
2A.
2B.
2C.
2D.
2E.
What is the atomic mass of Na:________________
What is the atomic mass of CL:_________________
What is the FORMULA weight of NaCl:_______________
What is the mass of the NaCl from the lab:_____________
Calculate the moles of sodium chloride used:
3. What is the experimental mole ratio of baking soda (NaHCO3) to sodium
chloride (NaCl)? (answer to 1 : answer to 2)
4. Write a balanced equation for the reaction that took place in the experiment.
5. According to the balanced equation, what is the theoretical mole ratio of
baking soda to sodium chloride? (Hint: look at the coefficients in #4)
6. Was the experimental mole ratio exactly the same as the theoretical mole
ratio? If not, give some possible reasons.