Chemistry 110 Capstone Lab

Chem. 110 Name:______Chemistry 110 Capstone Lab

In this experiment you will react a known amount of Sodium bicarbonate and hydrochloric acid solution. You will first predict the mass of the sodium chloride that will be produced and compare this with your actual results. 1. Measure, and record, the mass of a clean and dry evaporating dish. (Do not “tare” the dish) 2. Add 2.0 to 2.5 grams of sodium bicarbonate (or baking soda) and record the mass of the sodium bicarbonate and dish. Record this data in the table below. 3. Calculate the mass of sodium bicarbonate used. From the mass of sodium bicarbonate you weighed out, calculate the volume (ml) of 3.00 M hydrochloric acid you will need to use to react all of the sodium bicarbonate, and calculate the (theoretical) mass of the sodium chloride you will produce.

Mass of evaporating dish

Mass of dish and NaHCO3

Mass of NaHCO3 used

4 points for completed table –3 points if mass used is not between 2.00-2.50 g A) Calculate the mass of the sodium bicarbonate used:

Mass of dish and NaHCO3 - mass of empty dish = g NaHCO3 Answer______Below is the balanced equation for the reaction between hydrochloric acid and sodium bicarbonate? Give complete setups of our calculations in the space below and on the prediction sheet(page 2). Give the prediction sheet to your instructor and get his/her initials before beginning the experiment. Balanced equation: NaHCO3 (s) + HCl (aq)  H2O (l) + NaCl (aq) + CO 2(g)

B) Using the mass of sodium bicarbonate you weighed out, calculate the volume (ml) of the 3.00 M hydrochloric acid solution that will be used:

3 _____g NaHCO3 X 1 mole NaHCO3 X 1 mole HCl X 10 ml soln = ml HCl soln.

84.01 g NaH CO3 1 mole NaHCO3 3mole HCl

Answer______C) Using the mass of sodium bicarbonate you weighed out, calculate the mass of the sodium chloride product that will be made:

______g NaHCO3 X 1 mole NaHCO3 X 1 mole NaCl X 58.45 g NaCl = g NaCl

84.01 g NaH CO3 1 mole NaHCO3 1 mole NaCl

4 points this page

Answer______Instructor Initials:______Do not ask for your instructor’s initials until you complete page 2 1 Name:______

Give this to your instructor before you continue the experiment Chemistry 110 Capstone Lab prediction sheet

A) Calculate the mass of sodium bicarbonate used

Mass of dish and NaHCO3 - mass of empty dish = g NaHCO3

4 points Answer______

B) Using the mass of sodium bicarbonate you weighed out, calculate the volume (ml) of the 3.00 M hydrochloric acid solution that will be used:

3 _____g NaHCO3 X 1 mole NaHCO3 X 1 mole HCl X 10 ml soln = ml HCl soln.

84.01 g NaH CO3 1 mole NaHCO3 3 mole HCl

7 points

Answer______

C) Using the mass of sodium bicarbonate you weighed out, calculate the mass of the sodium chloride product that will be made:

______g NaHCO3 X 1 mole NaHCO3 X 1 mole NaCl X 58.45 g NaCl = g NaCl

84.01 g NaH CO3 1 mole NaHCO3 1 mole NaCl

7 points

Answer______

Turn this sheet into your instructor before you continue the experiment

Add back half the points subtracted from page 2 if corrections were made on page 1 2 18 points this page

4. Set up a steam bath. 5. From the dropper bottle. into a 10 ml graduated cylinder , carefully measure out the calculated volume (ml) of hydrochloric acid solution you will use. If any acid is dripping from the dropper bottle inform the instructor immediately and do not let it contact your skin. Do not squeeze the dropper bottle too much. Safety Caution!! In this experiment you are using 3.00M Hydrochloric acid (HCl) solution. This is a strong acid and it is fairly concentrated. It could burn your skin. Make sure you are wearing goggles . Do not touch the acid. Do not be sloppy. If a spill occurs, inform your instructor immediately. If any acid comes in contact with your skin wash the affected area and tell your instructor immediately.

Volume of HCl measured

Must be within 0.10 of predicted volume or – 2 points

Mass of NaHCO3 used

Predicted amount of NaCl

3 points for completed tables 6. Slowly add the hydrochloric acid soln. to the sodium bicarbonate in the evaporating dish. Do not set the evaporating dish on the steam bath until you have added all of the HCl solution, and you see no more evidence of reaction. 7. Set the evaporating dish on a steam bath. Heat the apparatus until the sodium chloride appears to be dry, (you will not see any steam coming from the dish) Do not leave you flame unattended. 8. Weigh the dish and product. Record the mass 9. Heat the dish and product to constant mass (last two weighings must be different by less than .2 grams

Mass of dish and product 1st heating

Mass of dish and product 2nd heating 3 Mass of dish and product 3rd heating if necessary

Mass of dish and product 4th heating if necessary

4 points for table Difference between the last two masses must be >0.20 g or – 3 points

7 points this page

Calculations Show all units and correct significant digits

1. Calculate the mass of solid sodium chloride produced

Mass of dish and NaCl (end product) - mass of empty dish = g NaHCl

5 points Answer______2. Calculate the difference(error) between the predicted (theoretical) amount of sodium chloride and the actual (experimental) amount of sodium chloride produced.

Mass of predicted NaCl – Mass of NaCl produced = error

5 points

Answer______3. Calculate the percent difference(percent error).

error in NaCl produced X 100 Mass of predicted NaCl

5 points

Answer______Questions and Answers: Give three reasons why the amount of NaCl you actually produced is different from the predicted amount? Be specific if your experimental (predicted) yield of NaCl is higher or lower than the actual yield then explain why.

6 points

21 points this page Total Score is out of 50