AmMay"i8Sarm'}     Philadelphia  College  of  Pharmacy.  253 
QUANTITATIVE  ANALYSIS. 
Atomic  Weights. — Ag  107*66,  Br  7976,  C  11*97,  CI  35*37,  H  10,  K  ^9*03,  N 
14*01,  Na  23*0,  o  15 -96,  S  31  "98. 
A— (1)  Give  an  outline  of  the  gravimetric  analysis  of  magnesium  sulphate 
for  magnesium  oxide,  sulphur  trioxide  and  water  of  crystallization,  mentioning 
the  chemical  formulas  for  the  precipitates  produced  and  for  the  substances 
weighed  at  the  end.  (2)  Outline  the  calculations  by  which  you  would  compute, 
the  percentage  amount  of  each  constituent  found. 
B — (1)  Describe  the  gravimetric  estimation  of  sodium  hypophosphite  which 
you  made  during  this  term.    (2)  Write  equations  for  the  reactions  involved. 
(3)  How  many  molecules  of  sodium  hypophosphite  are  indicated  by  one  mole- 
cule of  the  substance  from  whose  weight  the  result  was  calculated  ? 
C—  (1)  Show  upon  your  paper  the  means  which  you  take  to  find  how  much 
N 
absolute  acetic  acid  1  c.c.  of  -KOH,  V.  S.  will  neutralize.  (2)  5*986  grammes 
of  a  sample  of  acetic  acid  requires  36  c.c.  of  —  KOH,  V.  S.  to  neutralize  it. 
1 
Explain  why  each  c.c.  of  the  V.  S.  used  corresponds  to  1  per  cent,  of  absolute 
acetic  acid.  (3)  How  many  grammes  of  absolute  acid  are  present  in  one 
litre  of  the  preceding  sample,  if  the  specific  gravity  of  the  liquid  is  1  -048  ? 
(4)  How  many  cubic  centimetres  of —KOH,  V..S.  will  be  needed  to  neutralize 
1  kilogramme  of  acetic  acid  containing  36  per  cent,  of  the  absolute  acid  ?  (5) 
How  many  grammes  of  absolute  acetic  acid  will  this  same  volume  of  —  KOH, 
1 
V.  S.  neutralize  ?  (6)  A  sample  of  acetic  acid  has  a  specific  gravity  of  1  '048  and 
contains  36  per  cent,  of  absolute  acetic  acid,  how  many  cubic  centimetres  of 
the  sample  will  be  needed  to  neutralize  20  c.c.  of  —  KOH,  V.  S.  ? 
D — Give  the  successive  steps  in  the  volumetric  estimation  of  potassium  bitar- 
trate  by  means  of  —  oxalic  acid,  V.  S.,  using  phenolphtalein  as  indicator. 
E — (1)  How  many  grammes  of  pure  Na2S2035H20  are  used  to  make  one  litre 
Gf—  V.  S.  ?    (2)  Explain  why  this  quantity  is  used.    (3)  What  indicator  is 
employed  with  this  V.  S.  ?  (4)  Tell  how  the  indicator  behaves.  (5)  Name  the 
four  official  substances  which  you  estimated  with  this  V.  S.  during  the  term, 
(6)  Tell  how  each  was  prepared  for  titration.  (7)  Name  an  official  substance 
in  the  estimation  of  which  by  residual  titration  you  employed  this  V.  S.  (8) 
Name  the  other  reagents  employed  in  this  same  estimation. 
F—  A  dry  sample  of  potassium  bromide  contains  potassium  chloride.  0*500 
gramme  of  the  sample  requires  43  c.c.  of  —  AgN03,  V.  S.  for  complete  precipi- 
tation, what  per  cent,  of  potassium  chloride  is  present? 
