806
E D G A R T. W H E R R Y A N D EDGAR F. S N I T H
phuric acid
(1.1).
T h e current registered
I
ampere and 4 volts.
111
four minutes the solution was colorless. T h e current was allowed to act for ten minutes.
Volume of the sollition . ....... = I O cubic ceiitimeiers. 0 . I I j u gr:1111 copper. Copper sulphate .................... rllurnitiiurn sulphate. ... ........ : 0. I gram alutniiiiuiri. Siilphuric acid .................... :- 0 . 5 cu\iic ceiitinietrr. Current .......................... : L 1-1.6 ampere. Pressure 4-4.5 volts. Tinie ............................ I O iiiiiintes. Cojpri.found.. ..................... o.r150 f i r ~ i i0~. 1,1 5 . : gram, o . r l j z gram.
A low current (0.01 ampere and 2 volts) was passed through zinc sulphate in the presence of 0 . 2 5 cc. of sulphuric acid. I n twenty niiiiutes t h e mercury had increased 0.0006 grain in weight. Iron sulphate containiiig 0 . I i I O gram of iron, acidulated with 0.5 cc. of acid, with a crirrent of 0.01 ampere and a pressure of 2 volts gave in thirty iniiiiites 0.0434 gwni of iron. ll'hen I cc. of acid was prese n t , a current of 0 . I ampere with a pressnre of 2 volts gave 0.091 I gram of metal. T h e separation of copper from zinc was attempted but it was not successful. A copper solution coiitaiiiing 0 . 1 1 5 0 grain of copper in the presence of 2 . 5 cc. of acid and a current of 0 . 6 ampere and three volts, caused the mercury to increase in weight G. 1360 gram, showing that 0 . 0 2 1 2 gram of zinc had also been deposited. T h e separation of copper from iron as tried, but this, too, f-ailed. \&'it11 a current (like that given in the preceding paragraph) iron was detected i n the mercury, and in thirty niiiiutes the solution still showed t h e presence of copper. 0 . 2 5 cc. of acid was present. The iron .seemed to hold back the copper. When 3 cc. of acid were present in a solution of iron sulphate, containing 0 . I gram of iron and it was eiectrolyzed with a current of two amperes and four volts, 0.069 gram of iron went into the mercury. T h e experiment was repeated after the addition of -1. CC. of acid. Even this quantity failed to hold u p all the iron. T h e separation, therefore, of iron froin copper and of iron from zinc was unsuccessful. ~ . S I ~ E R S I T Y(11-
PENXSTLVASI.~.
[CONTRIBUTION F R O X T H E J O H S ~ I A R K l S O X1+.41$0R.&TORY OF CHE!dIJTRY.]
THE USE OF A ROTATING ANODE IN THE ELECTROLYTIC PRECIPITATION OF URANIUM AND MOLYBDENUM ET
EDGART.
IVHERKY A S D E l X A X 19. lqr ;.
F.SiZIITIi
Received Blarch
I. URANIUM The earl!. suggestion o f Sinith' that imiiiiiini could be cuniplctely precipitated b!. the current from an :icctr:tc- electrolyte has been ainp1~-yeriAni. Ck. J . , 1, 329.
USE O F A ROTATING ANODE
807
fied, and the purpose of these lines is only to record the conditions under which the deposition takes place when using a rotating anode. T h e salt applied in the experiments was uranyl sulphate. T h e form of apparatus and mode of rotation have been fully discussed in the numerous communications from this laboratory relating to the rapid precipitation of metals. It will not be necessary either, to comment further upon the form in which tlie uranium is precipitated or upon the subsequent treatment of the deposit. These points have been sufficiently dwelt upon in earlier communications.’ T h e results and conditions are : YSOJ
Present h-0.
iii G r a m s
I
0. I527
2
0.1 j27
3 4 5 6
0.2613 0.2613 0.2613 0.2613 0.2613 0.2613 0.2613
7
s
9
Acetic Acid cc.
Sodium Acetate i n Grains
C u r r e n t in -4mperes
Volts
Time in hlinrites
Temp.
ord.
3 3 7
14
18
I2
I5
I5
S
4
I2
4 4 4 4 4
I2
3 15
I2
IO
(‘
60° 50 50 50
I2
IS
I2
25
50 50
I2
30
50
UDX Found
in G r a m s
0.1j13 0. I525 0.2611
0.0344 0.0530 0.1074 0 . I935 0.2467 0.2611
Ani.
Carbonate i n (;ranis IO
11
0.2613 0.2613
0.2600
0.2613
From both of these electrolytes the precipitation is not only complete but exceedingly rapid ; hence, this method for the determination of uranium will recommend itself to the mineral analyst. T h e following curve was plotted from the preceding experiments.
I
L
Crm\’E I.
Kate of deposition of U r a n i u m Sesqnioxide
11. Molybdenum From acidulated molybdate solutions the hydrated susquioside is completely precipitated as an adherent deposit 011 the cathode. T h e pro-
‘ 8mith’s “Electrochemical iltl1~ysls,”p. 94
808
T H E O D O X E W. RICHARDS A S D G E O R G E S. FORRES
cedure has given an excellent and satisfactory method for the estimation of molybdenum as well as a most gratifyiiig inearis of separating it from t h e alkali metals. T h e conditions \\.ere as folloivs : hlO0,~
NO,
I
Present iri Grams 0 . I200
Dilute Potassium Sulphnric Sulphate Acid ( I : I O ) incc. i n tirams 2
Cuyrciit lIOO.,
111
Amperes
Volts
'l'i me
I
5
16
30
16 16
5 9
1;ou
I/d
c.rrg7
2
0. I2CX)
7
I
5
3 4 5 6
0. I200
2
I
3
u.1200
2
1
I6
15
0 . I200
2
I
5 5
16
20
0.I
0. I 2 0 0
2
I
>
16
25
0.IIcjS
From these data t h e following
curie
u-as clran-ii
O.O.;jj
0.0603 0.1026
190
:
.to
CI
,
CCKVE, I1
K a t e of i l r p o ~ i l l u i !uf ~ ~ ~ ~ ~ ~ ~ ~ I Sesqiiioxirir ~ I C I I I ~ I I I
The rapidity ivitli which the oxide separates and the ease with ivhicli the determination of molybdenum ma!. be carried out i t i this way bids fair to render the electrolytic procedure the preferable method with all those who acquaint t h e m s e l ~ e swith it. L ~ S I Y I ~ X S I TOYF
~Eh'SSSI,Y.+SI.\.
c 0 1.L E(; E , ] THE QUANTITATIVE SYNTHESIS OF SILVER NITRATE AND THE ATOMIC WEIGHTS OF NITROGEN AND SILVER. [Co S T R 1I>u1'IOSS
I:R O M 1'H E
CH EX1 1CAI.
BY T I I B O D O K E V ' I L L I A M K X C I I A R D S
L A ll OK A TCIK Y 0 1.'
A X 0
Keceived February
Gt!onc:E
I .A K \-.A
R I)
SHXSNON POKlitS.
~ j 1, 90;.
Introduction T h e composition of silver nitrate is one of the questionable premises in the lively argunierit which has recently takeu place cvncerniug the atomic weights of nitrogen and silver.' Altliougli Stas's syntheses of this salt were carried out on a large scale, and far inore carefully than those of anyone before him, several points coiicerniiig the details 01 the work were not iiivestigated with the care which moderli physicochemical T h e reader is referrerl for a convenient ri.iuln6 t o t h e Rel'ort of the 1 t i t e r 1 1 ~ tional Cotnniittee o n .Itornic TVeights, 'l'hix Jo~iriiztl. 28, I ( 1906). .ind ni:i!?y otllrr places ; also to Cla.rke, 'l'his Jonrn:d, 28. 293 ( r C . 0 5 ) ; Gr:iy, J. Cl1e111. Sdc. I I,o11tion). 89, 11;; ( r g c 6 ) .
