experiment of evaluation of gas law constant i need to give answers to this ques

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experiment of evaluation of gas law constant

i need to give answers to this question

here is what i did in my experiment

Needless regelion and iccidenis can be avaided it tre ink he doesn't break free while it is reacting. PROCEDURE alculaie the mass of magnesivm necessary vo evolve 80 ml. of H a STP. Then weigh approximaiely this quantity of Mg ribbon on the top loading balanct to the nearest me (0.001 ) I 2). approximately 8 mL,of concenowcd Hat0tudiomeer rube. with your wash bottle. acid thas mighi havr adhered to he eudiomeser walls. Coil the weighed ribbon imo the eudiomeser tube, approximaiely 5 to 10 em from the open end. (Copper wire d th ibbo helps to keep i in place.) Fill the wbe widh waier and invent iato a saitable 2 In wash down inio the tebe any suip of Mg r o vessel nearly filled with water. The vol with warer. Recoed the initial reading in your laboraiory n 10-1). eudiomcier volume should read zero if the tube is filled completely oiebook. Clamp the tube in pesition (Figure h water. The 3. The concenlresed HC1 will gradually difluse dows to the Mg and seaci with in. The ME may break free from.the copper wire. Tiliche tube to ensure hai ile M, does noi sick lthe sides of the tube. After reacuan has ceased it poseble·adrosuhe liquid levtl in te iube othe level of i.quis in he vessel. The Eas pressone in the lube is then equai vo inksphernc pressure. il the difference in levels is larg, it must be meassred as shown in F-gure 10-1 4. Recerd the semperacuit of the water in the vessel ai I-min iniervais for 3 min. Take the average valuc as 5. Repeat the experiment lor a total of four deserminations 6. Calculase the numbes of moles of magnesium used as a rescianm your gas iemperalure. Mass of Mgle) Number of moles of Mg-2431 pmol 7. Calculale the correcied prcssure for the expenimeni as described above using the observed berometric pressure for the das

Explanation / Answer

1. The largest source of experimental error in the determination of R is the error in the liquid level in the eudiometer tube, placed in the beaker.

2 a. If the liquid level in the eudiometer tube is lower than that in the beaker, and it is not taken into consideration in the calculations, then the R-value increases.

Explanation: The volume of H2 gas (V) = final reading - initial reading

i.e. V value increases and since R = PV/nT, R-value does also increase. (R is directly proportional to V)

b. If the balance used to weigh magnesium gives a mass that is higher than actual, then the R-value decreases.

Here, no. of moles of Mg (n value) increases and since R = PV/nT, R-value decreases. (R is indirectly proportional to n)

c. If some H2 escapes into the beaker during the reaction, then the R-value decreases.

Here, the pressure (P) of H2 decreases and since R = PV/nT, R-value decreases. (R is directly proportional to P)

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