posted by Jena on .
Performing the same experiment described on your lab manual, a student used a 0.358 g sample of Alka-Seltzer and the mass of CO2 was found to be 0.102 g. Based on this result, answer the following questions:
Determine the mass of NaHCO3 that produced the CO2 in the experiment.
Determine the % mass of NaHCO3 in the sample.
Determine the mass of NaHCO3 in the tablet assuming the mass of the tablet is 3.50 g.
How do i do the second and third questions?
I answered this same question for someone earlier but I can't find it. I think I erred in that post because I don't know the reaction. What are the conditions under which the loss of CO2 occurred?
Is that a titration experiment or was the tablet heated? If heated, at what T?
OK. I found the other post and you're the one who posted it. Therefore, disregard that post until you answer the questions about how the tablet was treated.
reaction between NaHCO3 and HCl
I did the equation of the % mass but its wrong
I want to know how the tablet was treated. You make reference in the problem to "Performing the same experiment described on your lab manual, a student used a 0.358 g sample of Alka-Seltzer ......." So you know how the sample was treated but I don't. Was it titrated with something such as HCl? heat to drive off CO2. If so what temperature was used.
HCl is added to NaHC03 .
HCl + NaHCO3 => H2O + CO2 + NaCl
Convert the 0.102 g CO2 to g NaHCO3.
0.102g CO2 x (molar mass NaHCO3/molar mass CO2) = 0.102 x 84/44 = 0.195.
Is that 0.195 you posted what you obtained.
Then %NaHCO3 = (0.195/0.358)*100 = about 54.4%. Check that.
If your earlier reply meant you tried these numbers and the data base said it was wrong then I need the procedure written out for me. This answer is right for what you've posted.
Yes its correct, but how about he mass of NaHCO3 in the tablet assuming the mass of the tablet is 3.50 g
That must be for a part of the problem you didn't post.
If the tablet is 54.4% NaHCO3 and the tablet has a mass of 3.50 g, then plug these numbers into the % formula and calculate mass NaHCO3.
(mass NaHCO3/mass tab)*100 = %
(x/3.50)*100 = 54.4
Solve for x = mass NaHCO3.