Emily Jennings
Mr. Wallace
Chemistry Lab Report
28 March 2011
Stoichiometry Lab
Purpose: to determine the chemical equation and the molar ratios for sodium bicarbonate and
hydrochloric acid.
Materials:
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Sodium bicarbonate
3M hydrochloric acid
Ring stand
Ring
Evaporating dish
Watch glass
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Iron gauze
burner w/tubing
scoopula
Crucible tongs
Disposable pipet
Beaker
Procedure:
1. Clean and dry an evaporating dish and a watch glass. Dry the dish over a gentle
flame for 1-2 minutes to drive off any excess water. Use tongs to handle the dish during
the experiment. Determine the mass of the evaporating dish to 0.01 grams.
2. With a scoopula, add between 2 to 3 grams of sodium bicarbonate to the evaporating
dish. Mass the dish and bicarbonate to 0.01 grams.
3. Obtain about 10 mL of 3 M HCl in a small beaker. Gradually add the HCl to the
evaporating dish using a disposable dropper.
4. Continue adding HCl a little at a time while swirling and stirring the evaporating dish
to mix the chemicals. Continue adding the HCl until no further reaction is observed. Do
not add more acid than is needed. You may obtain additional acid if necessary.
5. Set up the ring stand with the ring and wire gauze. Place the evaporating dish on the
wire gauze and start heating gently. After 2-3 minutes, increase the flame to boil the
liquids away while keeping the watch glass over the dish. Be careful that it doesn’t boil
over.
6. As the reaction products become dry, there will be a tendency for the product to spit
particles from the crucible. Take care to keep the watch glass over the evaporating dish
to minimize any loss of product.
7. When the product is dry, remove the evaporating dish from the heat. If any product
has stuck to the watch glass, scrape it back into the dish with a Scoopula or wash it back
into the evaporating dish with deionized water and dry further.
8. When all liquids are evaporated, allow the evaporating dish to cool and determine its
mass. To the nearest 0.01 grams.
9. Put the evaporating dish back on the heat for a final drying cycle, cool, and then mass
again to the nearest 0.01 grams. The two masses should be within 0.02 grams. If not,
return for another drying cycle.
Data Analysis:
Material
Amount
Mass of evaporating dish
46. 64 g
Mass of evaporating dish + sodium
bicarbonate
48.59 g
Mass of sodium bicarbonate
2.95 g
Molar mass of sodium bicarbonate
104.07 g/mole
Moles of sodium bicarbonate
0.03 moles
Mass of evaporating dish + product
48.56 g
Mass of product
1.92 g
Molar mass of product
58.44 g NaCl/ mole
Moles of product
.03285 moles
% yield = 2.95 g
1mole
mole NaHCO3
= 2.05 g NaCl (theoretical)
1.92/2.05 x 100 = 93.655 yield
% Error:
exp – accepted/ accepted x 100
1.92-2.05/2.05 x 100 = 6.34%
Balanced Equation:
mole NaHCO3
84.01 g NaHCO3
58.44 g NaCl
1 mole NaCl
NaHCO3+HCL -à NaCl+H2O+C02
Sodium bicarbonate is a chemical compound with the formula NaCHO3. Is has a white solid that
is crystalline but appears as fine powder. It has a salty taste to it and is dissolved into many
mineral springs. It has come to be known by many different names and is used in various ways
such as baking soda, cooking soda and bread soda. Sodium bicarbonate is not only a baking
ingredient but used in other ways as well. Sodium bicarbonate is and antacid used to relieve
heartburn as well as indigestion. This comes in a tablet as well as powder that you take by
mouth. This is a pill necessary by prescription. An overdose of sodium bicarbonate can also be
harmful to your body so it is necessary to maintain a healthy balance.