ch9 bs labm

BAKING SODA LAB M NAME____________________

PURPOSE: Use chemical equations and moles in the lab

DISCUSSION: Sodium bicarbonate, NaHCO3 (b.s.) , reacts with hydrochloric acid solution to produce carbon dioxide gas, salt, and water. The water can be evaporated by heat.

PROCEDURE: Weigh an empty e dish, then add about 2g of bs, weigh again. Place a paper towel under the e dish, then add hydrochloric acid with a dropper, stirring with a stirring rod. It will probably take about 2 droppers full. Try not too add too much HCl, because we will have to evaporate the excess. When the solution looks clear, and a drop of HCl produces no reaction, note the temperature. Place an identifying mark (initials) on the e dish, then evaporate the water by placing it in a drying oven overnight. The next day, remove and mass (use the same balance for all massing). Observe the shape of the crystals, then wash out the dish. Do another trial if directed; if not, remove your initials with alcohol.

Room mass mass solution mass

DATA: temp e dish edish&bs temp edish&salt

Trial 1

Trial 2

CALCULATIONS: mass bs moles bs mass salt moles salt

Trial 1

Trial 2

CONCLUSIONS:

1. Write a balanced chemical equation for the reaction; include states.

2. What were the bubbles?

3. What was in the edish when the bubbling stops, before heating it?

4. Why did the bubbling stop?

5. Which reactant is the limiting reactant? Which reactant was in excess?

6. What was removing by heating?

7. What is in the edish after heating? What is the shape of the crystals?

8. What is the mass of 1 mole of each reactant and product. (Use the P.T.)

a. sodium bicarbonate =

b. hydrochloric acid =

c. carbon dioxide =

d. salt =

e. water =

9. Find the % yield by dividing the moles of salt we got moles of salt expected. (the closer to 100%, the better.)