Page 20 - Referance Guide For Pharmaceutical Calculations (Naplex, Fpgee and Ptce)

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The amount of drug after the addition of tablets: = 710 x 50 x (273 +0)
760 x (273 +25)
= 1000 mg + 1250 mg
= 2250 mg = 42.79cc

This amount present in 500cc of solution: 220.(c) The calculation of molar gas constant R can
be calculated by:
= 2250 mg/500cc = 4.5 mg/cc
= 22.5 mg/5cc. PV = nRT where

216.(a) A 5% error is permissible, therefore one can P = 760 mm Hg = 1 atm
say: V = 22.4 liters
n = 1 mole
For 5 mg error we can weigh 100 mg R = ?
o
For 4 mg sensitivity ? T = (273.16 + 0) = 273.16 K

o
= 4 x 100 = 80 mg weighable. R = 1 x 22.4 = 0.082 atm lit/mole K
5 1 x 273.16

217.(a) A 1% error is permissible, therefore: 221.(c) 74.07 liters.

For 1 mg error we can weigh 100 mg PV = nRT where:
For 3 mg sensitivity ?
P = 740/760 atm
= 3 x 100 = 300 mg is minimum weighable. V = ?
n = 3 moles
218.(b) The balance has 3 mg sensitivity and 150 mg R = 0.08205 lit atm/mole deg
o
minimum weighable quantity, therefore: T = 273 + 20 = 293 K

For 150 mg weigh 3 mg error is permitted V = 3 x 0.08205 x 293
For 100 mg weigh ? 740/760

= 100 x 3 = 2% = 74.07 liters
150
222.(b) 31.41 gm/mole
219.(b) The volume of gas can be found by the
following formula: PV = g x R x T where:
M
P1V1 = P2V2 P = 780/760 atm
T1 T2 V = 500cc = 0.5 liter
g = 0.5 gm
Where P = Pressure in mm Hg, M = ?
V = Volume of gas R = 0.08205 lit-atm/mole deg
o
T = Temperature in Kelvin T = 273 + 120 = 393 K

V2 = P1 x V1 x T2 M = g x R x T = 0.5 x 0.08205 x 393
P2 x T1 PV 780/760 x 0.5

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