Instructions: Read the lab first and then answer the pre-lab questions at the end. Bring the pre-lab questions and answers on a piece of paper to class with you on the day of the lab
Hydrate of Baking Soda Lab
Purpose:
To determine the
ratio of NaHCO3 (baking soda) to water by mass and by moles. Regular baking soda has a certain amount of
water in it (this is called the hydrate).
After heating, you will drive off the water and make baking soda anhydrate.
Safety: Remember that hot
crucibles do not like cold water.
ALWAYS WEAR GOGGLES!
Procedure:
Record mass of crucible and lid on data table.
2.
Put enough baking soda into the crucible to fill the crucible up 1/3 of
the way.
Record the mass of crucible/lid and baking soda
(hydrate) on the data table.
for 5 mintues.
Record
as mass of crucible/lid and baking soda
(anhydrate) 1 on the data table.
Record
the mass of crucible/lid and baking soda
(anhydrate) 2 on your data
table.
6. If your value of anhydrate 1 and anhydrate 2
are within 0.1 grams of each other, you are ready to move on. If they are not, then reaheat the crucible
until you do get results which are 0.1 gram different.
7. Clean up your lab area and do the questions.
Pre-Lab Questions: You do not need to copy the
questions
Data Table:
mass of crucible and lid
__________________g
mass of crucible/lid and baking soda
(hydrate) _________________g
mass of crucible/lid and baking soda
(anhydrate) 1 _______________g
mass of crucible/lid and baking soda
(anhydrate) 2 _______________g
Caluclations:
1. Use your data table to figure out the
following information:
mass of hydrated baking soda
____________________g
mass of anhydrated baking soda (your
final result) ____________g
Post-Lab
Questions: You don’t need to
copy the questions
1. How many grams of the baking soda hydrate
is baking soda and how many grams is water?
2. What percentage of the total mass of the
hydrated baking soda is Baking soda?
3. What percentage of the total mass of the
hydrated baking soda is water?
4. Divide the smaller mass answer to question
#1 into the larger mass answer. What is
the mass ratio of baking soda:water?
5. Convert the number of grams of water in your
hydrated sample into moles.
6. Convert the number of grams of baking soda
(anhydrated) into moles.
7. What is the mole ratio of Baking
soda:water? Remember, to find the mole
ratio, convert all grams of substance into moles and divide by the SMALLEST
number.
What is due
for this lab and in what order?
1. Pre-Lab Questions (don’t need to copy them)
2. Data table
3. Calculations
4. Post-Lab Questions (don’t need to copy them)