Test+15+-+Chloride+and+Salinity

__//**﻿Chloride and Salinity**//__

//Chloride is one of the major inorganic anions in salt water or freshwater. Originated from the dissociation of salts in water. // //Exampale: Sodium chloride or calcium chloride.// // These salts, and their resulting chloride ions, originate from natural minerals, saltwater intrusion into estuaries, and industrial pollution. //

//The total af all non-carbonate salts dissolved in water is Salinity //, it is usually expressed in parts per thousands. Unlike chloride concentration, you can think of salinity as a measure of the //total// salt concentration. Salinity is an important measurement in seawater or in estuaries where freshwater from rivers and streams mixes with salty ocean water. Since most anions in seawater or brackish water are chloride ions, salinity can be determined from chloride concentration.

//The following formula is used://

salinity (ppt) = 0.0018066 5 Cl– (mg/L)  //A Chloride Ion-Selective Electrode can be used to determine the chloride concentration, which is converted to a salinity value using the above formula.//


 * //__[|Salinity using a conductivity Probe] __//**

**Materials Checklist**


 * < <span style="background-color: transparent; color: #000000; display: block; font-family: Times New Roman; font-size: 16px; margin-left: 18.5pt; text-align: left; text-decoration: none; vertical-align: auto;"><span style="color: #ff00ff; font-family: Georgia,serif; font-size: 110%;">_ Power Macintosh or Windows PC ||< <span style="background-color: transparent; color: #000000; display: block; font-family: Times New Roman; font-size: 16px; margin-left: 9.5pt; text-align: left; text-decoration: none; vertical-align: auto;"><span style="color: #ff00ff; font-family: Georgia,serif; font-size: 110%;">_ wash bottle with distilled water  ||
 * < <span style="background-color: transparent; color: #000000; display: block; font-family: Times New Roman; font-size: 16px; margin-left: 18.5pt; text-align: left; text-decoration: none; vertical-align: auto;"><span style="color: #ff00ff; font-family: Georgia,serif; font-size: 110%;">_ Vernier computer interface ||< <span style="background-color: transparent; color: #000000; display: block; font-family: Times New Roman; font-size: 16px; margin-left: 9.5pt; text-align: left; text-decoration: none; vertical-align: auto;"><span style="color: #ff00ff; font-family: Georgia,serif; font-size: 110%;">_ tissues or paper towels  ||
 * < <span style="background-color: transparent; color: #000000; display: block; font-family: Times New Roman; font-size: 16px; margin-left: 18.5pt; text-align: left; text-decoration: none; vertical-align: auto;"><span style="color: #ff00ff; font-family: Georgia,serif; font-size: 110%;">_ Logger //<span style="background-color: transparent; text-align: left; text-decoration: none; vertical-align: auto;">Pro // ||< <span style="background-color: transparent; color: #000000; display: block; font-family: Times New Roman; font-size: 16px; margin-left: 9.5pt; text-align: left; text-decoration: none; vertical-align: auto;"><span style="color: #ff00ff; font-family: Georgia,serif; font-size: 110%;">_ 5 ppt salinity standard  ||
 * < <span style="background-color: transparent; color: #000000; display: block; font-family: Times New Roman; font-size: 16px; margin-left: 18.5pt; text-align: left; text-decoration: none; vertical-align: auto;"><span style="color: #ff00ff; font-family: Georgia,serif; font-size: 110%;">_ Vernier Conductivity Probe ||< <span style="background-color: transparent; color: #000000; display: block; font-family: Times New Roman; font-size: 16px; margin-left: 9.5pt; text-align: left; text-decoration: none; vertical-align: auto;"><span style="color: #ff00ff; font-family: Georgia,serif; font-size: 110%;">_ 10 ppt salinity standard  ||
 * < <span style="background-color: transparent; color: #000000; display: block; font-family: Times New Roman; font-size: 16px; margin-left: 18.5pt; text-align: left; text-decoration: none; vertical-align: auto;"><span style="color: #ff00ff; font-family: Georgia,serif; font-size: 110%;">_ 100-mL graduated cylinder ||< <span style="background-color: transparent; color: #000000; display: block; font-family: Times New Roman; font-size: 16px; margin-left: 9.5pt; text-align: left; text-decoration: none; vertical-align: auto;"><span style="color: #ff00ff; font-family: Georgia,serif; font-size: 110%;">_ small paper or plastic cup (optional)  ||
 * < <span style="background-color: transparent; color: #000000; display: block; font-family: Times New Roman; font-size: 16px; margin-left: 18.5pt; text-align: left; text-decoration: none; vertical-align: auto;"><span style="color: #ff00ff; font-family: Georgia,serif; font-size: 110%;">___ 500-mL bottle with lid__ ||<   ||

__<span style="color: #008000; font-family: Georgia,serif; font-size: 130%;">//**Testing Procedure**// __

<span style="color: #000080; font-family: Georgia,serif; font-size: 120%;">//1.Prepare the Conductivity Probe for data collection.//

<span style="color: #000080; font-family: Georgia,serif; font-size: 120%;">//a. Plug the Conductivity Probe into Channel 1 of the Vernier interface.//

<span style="color: #000080; font-family: Georgia,serif; font-size: 120%;">//b. Set the switch on the probe box to the 0-20000 µS range (0-13 ppt salinity).//

//<span style="color: #ff00ff; font-family: Georgia,serif; font-size: 120%;">2. You are now ready to calibrate the Conductivity Probe. // //<span style="color: #ff00ff; font-family: Georgia,serif; font-size: 120%;">· If your instructor directs you to use the calibration stored in the experiment file, then proceed to Step 3. // //<span style="color: #ff00ff; font-family: Georgia,serif; font-size: 120%;">· If your instructor directs you to perform a new calibration for the Conductivity Probe, follow this procedure: //

//<span style="color: #ff00ff; font-family: Georgia,serif; font-size: 120%;">First Calibration Point // //<span style="color: #ff00ff; font-family: Georgia,serif; font-size: 120%;">a. Choose Calibrate from the Experiment menu and then click. // //<span style="color: #ff00ff; font-family: Georgia,serif; font-size: 120%;">b. Perform the first calibration point by placing the Conductivity Probe into the 5 ppt salinity standard. The hole near the tip of the probe should be covered completely. // //<span style="color: #ff00ff; font-family: Georgia,serif; font-size: 120%;">c. Type “5” (the salinity value) in the edit box. // //<span style="color: #ff00ff; font-family: Georgia,serif; font-size: 120%;">d. When the displayed voltage reading for Input 1 stabilizes, click. //

//<span style="color: #ff00ff; font-family: Georgia,serif; font-size: 120%;">Second Calibration Point // //<span style="color: #ff00ff; font-family: Georgia,serif; font-size: 120%;">e. Place the Conductivity Probe into the 10 ppt salinity standard solution. The hole near the tip of the probe should be covered completely. // //<span style="color: #ff00ff; font-family: Georgia,serif; font-size: 120%;">f. Type “10” (the salinity value) in the edit box. // //<span style="color: #ff00ff; font-family: Georgia,serif; font-size: 120%;">g. When the displayed voltage reading for Input 1 stabilizes, click, then click. // <span style="color: #ff9c00; font-family: Georgia,serif; font-size: 120%;">//h. Rinse the electrode with distilled water and gently blot it dry with a tissue.//

<span style="color: #ff9c00; font-family: Georgia,serif; font-size: 120%;">//3. You are now ready to collect salinity concentration data.// <span style="color: #ff9c00; font-family: Georgia,serif; font-size: 120%;">//a. Place the tip of the electrode into a cup with sample water from the body of water you are testing. The hole near the tip of the probe should be covered completely.// <span style="color: #ff9c00; font-family: Georgia,serif; font-size: 120%;">//b. Monitor the salinity concentration value in the Meter window.// <span style="color: #ff9c00; font-family: Georgia,serif; font-size: 120%;">//· If the value is less than 13 ppt (the upper range of the Conductivity Probe), record this value on the Data & Calculations sheet. If you did a ¼ dilution of the sample, be sure to multiply this value by 4!// <span style="color: #ff9c00; font-family: Georgia,serif; font-size: 120%;">//· If the salinity value is greater than 13 ppt, go to Step 5.//

<span style="color: #ff9c00; font-family: Georgia,serif; font-size: 120%;">//4. Repeat Step 5 to obtain a second reading.// <span style="color: #ff9c00; font-family: Georgia,serif; font-size: 120%;">//5. If your salinity value is greater than 13 ppt, then the sample had a salinity value that is beyond the upper range of the Conductivity Probe. You will need to dilute the sample to a salinity value that is within the range of the probe. To do this,// <span style="color: #ff9c00; font-family: Georgia,serif; font-size: 120%;">//a. Use a graduated cylinder to add 100 mL of the water sample to a 500-mL bottle.// <span style="color: #ff9c00; font-family: Georgia,serif; font-size: 120%;">//b. Add 300 mL of distilled water to the sample in the bottle, screw the lid on, and shake it well.//

<span style="color: #000bff; font-family: Georgia,serif; font-size: 120%;">//c. **Important:** The sample has been diluted by a factor of 100/400 or ¼. Any salinity measurements made on this sample will have to be multiplied by a factor of 4 to account for this dilution.// <span style="color: #000bff; font-family: Georgia,serif; font-size: 120%;">//d. Repeat Step 3 to obtain a second reading.//

<span style="color: #3b00ff; font-family: Georgia,serif; font-size: 130%;">__//**DATA & CALCULATIONS**//__

<span style="color: #ff0000; font-family: Georgia,serif; font-size: 110%;">__//Method 2: Salinity Using a Conductivity Probe//__

<span style="color: #ff00ca; font-family: Georgia,serif; font-size: 130%;">**//(ppt)//** ||
 * = <span style="color: #ff00ca; font-family: Georgia,serif; font-size: 130%;">**//Column//** ||= <span style="color: #ff00ca; font-family: Georgia,serif; font-size: 130%;">**//A//** ||
 * = <span style="color: #ff00ca; font-family: Georgia,serif; font-size: 130%;">**//Reading//** ||= <span style="color: #ff00ca; font-family: Georgia,serif; font-size: 130%;">**//Salinity//**
 * = <span style="color: #ff00ca; font-family: Georgia,serif; font-size: 130%;">**//1//** ||=  ||
 * = <span style="color: #ff00ca; font-family: Georgia,serif; font-size: 130%;">**//2//** ||=  ||


 * <span style="color: #ff00ca; font-family: Georgia,serif; font-size: 130%;">**//Average//** ||

<span style="color: #002cff; font-family: Georgia,serif; font-size: 130%;">**//Column Procedure://**

<span style="color: #002cff; font-family: Georgia,serif; font-size: 130%; text-indent: 0.5in;">**//A. Record the salinity concentration as determined by interpolation of the calibration curve.//**

<span style="color: #002cff; font-family: Georgia,serif; font-size: 130%;">**//Field Observations (e.g., weather, geography, vegetation along stream)//**