Lab: Exploration of Avogadro's Law-Determination of Percentageof Sodium Bicarbonate in an Alka-Seltzer Tablet
1) One concern with setting up a closed system experiment wheregas is evolved during a reaction is the presence of leaks (anotherconcern is that the system will explode if too much gas evolves!).We know that some leaking of pressure occurs because after amaximum pressure is achieved it slowly starts to decrease withtime. Will a leak during gas evolution overstate or understate theamount of sodium bicarbonate in an Alka-Seltzer tablet and why?
2)In our rearranged Ideal Gas Law Δn=(ΔPV)/(RT) we considered Vand T to remain constant. Is this a reasonable assumption and why?Assuming that T increased as a function of the reaction, would thiscause an overestimation or underestimation of the amount of sodiumbicarbonate?
3) To calculate the amount of sodium bicarbonate, we assume thatthere was enough citric acid to react completely with the sodiumbicarbonate. However, if the citric acid is the limiting reagent,then the calculated amount for sodium bicarbonate would beincorrect. How could we experimentally test this possibility?Describe in two sentences how you would change the reactionconditions to account for this.
