5 Flashcards
(115 cards)
memorize the formulas
formula of Molality
moles / kg of solvent
formula of molarity
moles / L of solvent
formula of /MMoles
wt g
_____
M.W
formula or Meq
wt mg x verelance
____________
M.W
formula of osmolarity
wt g/L
________
M.W
X practice
look at page 2
1- amount of drug is 5 mg in 1 ml what the amount of drug in 1
tsp in microgram
a ) 5
b ) 25
c ) 500
d ) 2500
e ) 25000
e ) 25000
Answer:
1 tsp = 5 ml
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X = 5 x 5/1 = 25 mg = (25 x 1000) 25000 mcg
2- A solution is made by dissolving 17.52 g of NaCl exactly 2000 ml.
What is the molarity of this solution?
a- 3.33
b- 0.15
c- 1.60
d-3.00 x 10 -4
e-1.6x10 -4
b- 0.15
Answer :
Molarity=mole/volume (L)
1 Mole=molecular weight of subs. In 1 grams
No of Moles = wt / Mwt
So, molecular weight of NACL=23+34=57
So, Mole=17.52/57=0.307
So, Morality=0.307/2=0.153
3-5ml of injection that conc. 0.4% calculate the amount of drug?
a-0.2mg
b-2mg
c-200mg
d-2000mg
e-20mg
e-20mg
Answer:
0.4gm …100ml
X gm…5mL
X = 5 x 0.4/100 = 0.02 gm = (0.02 x 1000) = 20 mg
4-An elixir contains 0.1 mg of drug X per ml. HOW many micrograms are
there in one tsp of the elixir
A. 0.0005 micrograms
B. 0.5 micrograms
C. 500 micrograms
D. 5 micrograms
E. 1500 micrograms
C. 500 micrograms
Answer :
0.1 mg in 1 ml
X mg in 5 ml
X = 0.1
×5 /1 = 0.5 mg = 500 micro
5- sol contain D5W another one contain D50W we want to prepare sol cotain
D15W its volune is 450ml … how much ml we need of each sol
a) D50w/D5w=10/35
Answer:
try the choices ratio in the equation :
(C1
× V1) + (C2
× V2) = (C
× V)
( 50
× 10 ) + ( 5
× 35 ) = ( 15
× 45 )
Another answer :
(X) 50 ———- 10 15
± 5 = 10
15
(Y) 5 ———– 35 50
± 15 = 35
X / Y = 10 / 35 ———- Y = 3.5 X
X + Y = 450 ———- X + 3.5 X = 450
4.5 X = 450 ——— X = 450 /4.5 = 100
Y = 3.5 X = 3.5 x 100 = 350
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6- prescription
hydrocortisone 2%
Cold cream 60gm
You have concentrations of hydrocortisone 2.5% & 1% how many grams will
you use from two concentration?
a- 20gm from 1% and 40gm from 2.5%
b- 40gm from 1% and 20gm from 2.5%
c- 30gm from both
a- 20gm from 1% and 40gm from 2.5%
Answer:
try the choices ratio in the equation
( C1
× V1 ) + ( C2
× V2 ) = ( C
× V )
( 1
× 20 ) + ( 2.5
× 40 ) = ( 2
× 60 )
Another answer :
(X) 2.5% ———- 1 2 ± 1 = 1
2%
(Y) 1% ———– 0.5 2.5 ± 2 = 0.5
X / Y = 1 / 0.5 ————– X = 0.5 Y
X + Y = 60 ——– 0.5 Y + Y = 60
1.5 Y = 60 ———– Y = 60 /1.5 = 40
X = 0.5 Y = 0.5 x 40 = 20
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7-Prescription
hydrocortisone 2% w/w
Cold cream 60gm
you have hydrocortisone solu. 100 mg/ml .. how many milliliters will you use
from the solution ?
a.10 ml
b.20 ml
c.40 ml
b.20 ml
2% w/w = 2% x 100gm = 2 gm means the prep. needs 2 gm of
hydrocortisone
0.1 gm in 1 ml
2 gm in X ml
X = 1 x 2/0.1 = 20 ml
8- if we have 0.8687g cacl2 in 500 ml solvent , denisty of the solvent is 0.95
g\cm3 ….Find the molality
a- 0.0165 Molal
b- 0.0156 Molal
c- 0.0165 m
d- 0.0156 m
a- 0.0165 Molal
Answer :
Moles = mass/m.wt = 0.8687 / 111 = 0.00782
Weight = density × volume = 0.95 × 500 = 475 gm = 0.475 kg
Molality = moles / kg of solvent = 0.00782/0.475 = 0.0165 molal
- How gm of substance X must added to 2000 gm of 10% substance X
solution in order to prepare 25% of substance x solution
a) 10000 gm
b) 400 gm
c) 40 gm
d) 10 gm
e) 0.4 gm
b) 400 gm
Answer:
(C1 × V1) + (C2 × V2) = ( C × V )
( 100% × Xgm ) + ( 10% × 2000 gm ) = ( 25% × 2000+X gm )
100X + 20,000 = 50,000 + 25X
100X - 25X = 50,000 - 20,000
75X = 30,000 ….. X = 30,000/75 = 400 gm
Another answer :
100% ————– 15 25 - 10 = 15
25%
10% —————- 75 100 - 25 = 75
so the ratio between 100% : 10 % to reach 25% = 15 : 75
2000 gm —— 75
X gm ———— 15
X = 2000 x 15 / 75 = 400 gm
10- How much water (in milliliters) should be added to 250 mL of 1:500 w/v
solution of benzalkonium chloride to make a 1:2000 w/v solution
A/0.4L
B/2L
C/0.2L
D/ 0.05L
A/0.4L
Answer:
250/500 = 0.5
250/2000 = 0.125
0.5 ± 0.125 = 0.375
11-How many mOsm are present in 1 liter of sodium chloride injection
(Mwt: sodium chloride= 58.5) ?
308 mosm
Answer :
x Note ; normally conc. of NaCl injection = 0.9%
that means 0.9 gm in 100 ml ….. that means 9 gm in 1 L
x Step 1.
millimoles = wt (gm) / Mwt (gm) × 1000 = 9 /58.5 ×1000 = 154
Note ; millimole = wt (mg) / Mwt (gm)
x Step 2.
mOsm = millimoles x no. of dissosation particles =154 × 2 =308 mosm
12-A solution contains 448 mg of KCl (MW=74.5) and 468 mg of NaCl (MW =
58.5) in 500mL. What is the osmolar conc. of this solution ?
0.056 Osm/l
Answer :
x For ( KCl )
0.448 gm in 500ml
X gm in 1000 ml …… X= 0.896 gm
moles= 0.896/74.5 = 0.012
Osm= moles × no. of dissosation particles =0.012 × 2= 0.024
x For NaCl
0.468 gm in 500 ml
X gm in 1000 ml ….. X= 0.936 gm
moles= 0.936 /58.5 = 0.016
Osm= 0.016 × 2= 0.032
x Total osmalar conc. of sol. = 0.032 + 0.024 = 0.056 Osm/l
- A Patient weighting 80 Kg is supposed to receive a drug at a dose of
2mg/kg/day. What is the dose that the patient should take for each day:
A. 80 mg …..
B. 160 mg …..
C. 240 mg …..
D. 320 mg …..
E. 400 mg
B. 160 mg …..
- Drug X is a given to a 70 Kg patient at an infusion rate of 0.95 mg/kg/hr.
How much drug we need for a 12-hr infusion bottle
A. 798 mg …..
B.66.5 mg …..
C. 665 mg …..
D. 84 mg
A. 798 mg …..
- how many gm of water add to 5% KCL soln to make 180 gm of
solution(w\w)?
171 gm
Answer:
5gm————–100
Xgm————–180
X= 5x180/100=9 gm
So, the amount of water is:- 180 - 9 =171 gm
- hypoparathyroid patient with tingling and numbness has the following lab
result so what is value of calcium correlative to albumin when below 45
calcium:
result:1.6
normal value: 2.25-2.6
albumin
result: 34
normal value:18-56
a.2.3
b-1.5
c-2.5
a.2.3
N.B: 2.3 is a Conistant value you have to know
- in clinic patient prescriped with a 500mg dose of aspirin , initial plasma
conc is 100mg .. With half life 6 hours calculate total body clearance ?
a.0.5 L/hr
b.5 L/hr
c.50 L/hr
a.0.5 L/hr
Answer:
Vd = dose / initial conc = 500/ 100 = 5L ….. T1-2 = 6 hr
Cl = 0.693 Vd / T1-2 = 0.693 × 5 / 6 = 0.5775 L/hr
- aminophylline (80%theophylline) was prescriped for asthmatic patient in
a dose of 500mg , half life =6.93 hours how many hours will it take to reach
below 2 % ?
- aminophylline (80%theophylline) was prescriped for asthmatic patient in
42 hr
Answer:
(80%) …T1… (40%) …T2… (20%) …T3… (10%) …T4… (5%) …T5… (2.5%)
…T6… (1.25%)
Time = 6 × T1/2 = 6 × 6.93 = 41.5 hr