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!
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
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
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
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 donít 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 (donít need to copy them)
2.† Data table
4.† Post-Lab Questions† (donít need to copy them)