THE DISSOCIATION OF DOUBLE SALTS 
497 
THE DOUBLE CHLORIDE OF COPPER AND AMMONIUM. 
C 11 CL. 2XH.C1 + 2H 2 0. 
For these tests we used the salt crystals furnished by the 
Baker Adamson Company. The analysis of this salt compared 
favorably with the calculated composition which is: 
Per, Cent 
Cu 
22.89 
NH, 
Per Cent 
12.97 
Cl 
Per Cent 
51.16 
H 2 0 
Per Cent 
12.97 
Concentration 
CuCl 2 
NHjCl 
TEMPERATURE 
Teist No. 1 
.10365 
.40470 
Duration of Test 
Test No. 2 
.08954 
.37995 
From the formula of the double chloride of copper and am- 
monium, it is plain that the two salts have combined in such a 
way that the relative molecular weight is 134 of. the copper 
chloride to 107 of the ammonium chloride. If the salt does not 
dissociate we will expect then to find the salts in the diffusate in 
the proportion of (1) one of the ammonium chloride to 1.25 
of the copper chloride. The analysis, however, shows the pres- 
ence of about four times as much ammonium chloride as of the 
copper chloride. 
Concentration 
5 Per Cent 
CuClo 
NH 4 C1 
Temperature 
Room Temp. 
Test No. 1 
.07820 
.23149 
Duration of Test 
2 Hours 
Test No. 2 
.06680 
.20469 
The ammonium chloride is still present in an excess but not 
so much as in the first instance. 
Concentration 
5 Per Cent 
CuCl 2 
NH 4 C1 
Temperature 
Room Temp. 
Test No. 1 
.05428 
.10626 
Duration of Test 
1 Hour 
Test No. 2 
.05015 
.10690 
It is readily seen, from the results of the five, two, and one 
hour tests, that the difference is less in the shorter time tests. 
It is to be expected then that since the CuCl 2 diffuses at a 
more even-, rate, the ammonium chloride comes through very 
much faster during the first part of the test and decreases rap- 
idly until the weight of the copper chloride seems to approxi- 
mate the weight of the ammonium salt. 
32 
