Ans:
Alogliptin benzoate: Its molecular formula as per given structure is C25H27N5O4
Molar mass can be calculated by summing up the atomic masses
Molar mass of Alogliptin benzoate =
25* (12.0107 ± 0.0008) for carbon
+ 27* (1.00794 ± 0.00007) for hydrogen
+ 5* (14.0067 ± 0.0002) for nitrogen
+ 4* (15.9994 ± 0.0003) for oxygen
--------------------------------------------------
= 300.2675 ± 0.02
+ 27.21438 ± 0.00189
+ 70.0335 ± 0.001
+ 63.9976 ± 0.0012
------------------------
Mola mass = 461.51298 ± ? g/mol

Combine uncertainty in addition
? = Uncertainty = √ (0.02)2 + (0.00189)2 + (0.001)2 + (0.0012)2
= √ 0.0004 + 0.0000035721 + 0.000001 + 0.00000144
= √ 0.0004060121
= 0.0201497419338313
= 0.02
So molar mass with uncertainty
= 461.51298 ± 0.02 g/mol
= 461.513 ± 0.02 g/mol (rounded)

Metformin hydrochloride: Its molecular formula as per given structure is C4H12ClN5
Molar mass can be calculated by summing up the atomic masses
Molar mass of Metformin hydrochloride
= 4* (12.0107 ± 0.0008) for carbon
+ 12* (1.00794 ± 0.00007) for hydrogen
+ 1* (35.453 ± 0.002) for chlorine
+ 5* (14.0067 ± 0.0002) for nitrogen
------------------------------------------
= 48.0428 ± 0.0032
+ 12.09528 ± 0.00084
+ 35.453 ± 0.002
+ 70.0335 ± 0.001
-------------------------------------
Mola mass = 165.62458 ± ? g/mol

Combine uncertainty in addition
? = Uncertainty = √ (0.0032)2 + (0.00084)2 + (0.002)2 + (0.001)2
= √ 0.00001024+ 0.0000007056 + 0.000004 + 0.000001
= √ 0.0000159456
= 0.0039941942101531
= 0.00399
So molar mass with uncertainty
= 165.62458 ± 0.00399 g/mol
= 165.624 ± 0.00399g/mol (rounded)

MOLECULAR ABSORPTION SPECTROSCOPIC ANALYSIS OF IRON USING o-PHENANT...