I'm showing the procedure of the lab and what was asked. What I have question on is towards the end. Much help would be appreciated a lot!!
First I had to balance the equation given to me:
2 Na HCO3 (s) Δ over arrow (produces)
Na2 CO3 (s) + CO2 (g) + H2O (g).
From the lab observations:
A. Mass of evaporation dish & watch glass = 75.705 g
B. Mass of evaporating dish, watch glass, & NaHCO3 = 78.605
C. Mass of evaporating dish, watch glass, & Na2CO3 = 57.460 g
1.) Using your data, calculate the mass of Na2CO3 produced?
75.705g - 57.460 g = 18.245 g
2.) Calculate the mass of NaHCO3 that decomposed?
78.605 g - 75.705 g = 2.9
If correct sig figs, wouldn't the answer be 2.9000 or just 2.9?
Wouldn't this affect my answer if correct sig figs aren't correct?
4.) Using your data, calculate how many grams of Na2CO3, Theoretically should have been produced using stoichiometry? (Hint use your calculated amount of NaHCO3 to start the stoich... chart & refer to balanced.
baking soda Δ> carbon dioxide + water + sodium carbonate
2 NaHCO3 Δ CO2 + H2O + Na2CO3
Answer (I know this isn't right! Can someone break down the process including numbers of what to multiply with what etc.) :
2.900 g NaHCO3 x 1molNaHCO3/ 84.0059 gNaHCO3 x 1molNa2CO3/ 2 mol NaHCO3 x 105.988 g Na2CO3 / 1mol Na2CO3 = 1.829 g Na2CO3
Is that correct though?
Now #5 asks calculate percent yield & use experimental mass of Na2CO3 which is 18.245... & theoretical amount of Na2CO3 which is (1.829) BUT IDK IF THAT's RIGHT (please check my math!! THANKYOU SO MUCH...based on the stoichiometry...
18.245 / 1.829 x 100 = 997.5
That does not seem right though. so, where did I go wrong?
3 answers
4, right, but obviously something else is wrong.
5. What is wrong is your mass of the final is wrong.
You can't start out with the empty apparatus mass greater the final apparatus weight with product.
2. so is it 2.9000 because technically that's wrong cuz theres 3 digits on the right of the period right?
or is it 20.900 but that woudn't make sense. even if it was 02.900, the zero wouldn't matter. so what is the number may I ask?
so #4 is good?
#5 How do I fix it? Really confused at this point. Please help. Would really appreciate it.