How does your measured salinity for Ocean Beach water compare with the global average value for seawater (salinity = 35‰)? Explain why there is a difference if one is observed.
2. Comment on the "drinkability" of the water you obtained by distillation (with respect to salinity), by comparing it to the U.S. Public Health Service standard of 0.5 ‰.
3. What is the salinity of the water remaining in the flask at the end of the distillation? Is it different from the initial salinity of the seawater? Calculate the difference using the data that you gathered.
A. Desalination by Distillation
Table 1. Conductivity, salinity (ppt), and temperature (C) of seawater before distillation, distillate, and brine water after distillation conducted on (DATE)
Sample Seawater (initial, before distillation)
Salinity (%o) 27.2
Conductivity (mS/cm)
Temperature (C)
39.9
22.1
Distillate
0.0
0.00616
14.8
Brine (in flask after distillation)
39.1
43.9
11.7
B. Measuring Conductivity and Salinity
Table 2. Temperature (C), conductivity (mS or uS), and salinity (ppt) of seawater, lake water, tap water, and deionized water conducted on (DATE)
Sample type
Salinity (%o) 27.2
Conductivity (mS/uS)
Temperature (C)
Seawater (Ocean Beach)
40.0
22.1
Lake water (Lake Merced)
0.2
0.379
21.6
Tap water
0.04
0.0924
22.1
Deionized water
0.0
0.00215
21.8