Sodium Chloride

Sodium Chloride

Introduction to NaCl

Sodium chloride is a compound formed from the ionic bonding of sodium and chloride

Sodium chloride, also known as salt, common salt, table salt or halite, is an ionic compound with the chemical formula NaCl, representing equal proportions of sodium and chlorine. Sodium chloride is the salt most responsible for the salinity of the ocean and of the extracellular fluid of many multicellular organisms. In the form of edible or table salt it is commonly used as a condiment and food preservative. Large quantities of sodium chloride are used in many industrial processes, and it is a major source of sodium and chlorine compounds used as feedstocks for further chemical syntheses. A second major consumer of sodium chloride is deicing of roadways in sub-freezing weather

Sodium Chloride is one of the most important salts in nature and biological systems.Salts are inorganic compounds, which means they do not contain carbon and hydrogen together in one molecule. Salts form from a positively charged atom, called a cation (pronounced CAT-eye-uhn, attracting a negatively charged atom, known as an anion. This attraction is known as an ionic bond, and is key in maintaining the chemical structure of salts.

Introduction to the basics of reagents preparationName of experiment : AnalysisofaMixtureofNaHCO3andNaCl

PURPOSE:1. TodeterminethepercentofNaHCO3 inamixtureofNaHCO3andNaCl.2. Toseparatetwosubstancesbyachemicalreaction.

METHOD :

When a mixture of NaHCO3 and NaCl is treated with concentrated HCl, only NaHCO3 will react, whereas the NaCl will remain unchanged:

Thesampleof unknown contains two compounds (NaHCO3 and NaCl).TheresiduewhichresultsuponadditionofaqueousHClwilcontainonlyNaCl. PartoftheresidueistheoriginalNaClthatwaspresentandtheotherpartistheNaClformedasaresultofthereactionbetweenNaHCO3andHCl.

Since:ThemoleratiobetweentheNaClformedandtheNaHCO3reactedis1:1(e.g.,1moleofNaHCO3produces1moleofNaCl)ThemolarmassofNaClislessthanthemolarmassofNaHCO3Theotherproductsofthereaction(CO2andH2O)aregasesandwilbelosttothesurroundings.

Then the residue wil weigh less than the original sample and the sample will appeartohavelostmass.SincethemasslossisproportionaltothemassofNaHCO3 originaly presentinthemixture,themassofNaHCO3canbecalculated.The resultofthisanalysisis usualy given as the percentage of NaHCO3present in the original sample of unknowncomposition.

ProcedureObtain a sample (about 1.0 grams) of the unknown (NaCl + NaHCO3) mixture.

2. Record the unknown number in your Laboratory Notebook.3. Place a clean 50 mL beaker on a wire gauze and heat for three minutes at maximum flame temperature to remove all moisture from the beaker.

4. Allow the beaker to cool to room temperature.5. Mass the cooled beaker on the analytic balance (to the nearest 0.0001 g)

6. Add your sample in the beaker.7. Determine the exact mass of the beaker and its content s on the analytic balance ( to the nearest 0.0001 g).8. Determine the exact mass of the sample in the beaker by difference.9. In the fume hood, measure out 4-5 mL of concentrated hydrochloric acid (12 M) in your small graduated cylinder.

10.Record the volume of the acid to the nearest 0.1 mL.Note : You must measure out at least 4.0 mL of the acid. This will ensure that the HCl is NOT the limiting reactant.

11. In the fume hood, transfer the concentrated hydrochloric add to another small beaker and cover it with a watch glass.

12. If you measured out too much concentrated hydrochloric acid, dispose of it into an appropriately labeled waste container found in the fume hood.13. While in the fume hood, add by drops using a Pasteur pipette the concentrated hydrochloric acid to the sample and observe the effervescence.Note : If the effervescence is too vigorous, slow down the rate at which the concentrated hydrochloric acid is added. This is to avoid splattering of the sample.This step is completed when all of the concentrated hydrochloric acid has been added to the sample.

14.Heat the beaker in the fume hood until the sample appears dryNote : Avoid strong heating, especially at the beginning since the excess hydrochloric acid may boil too vigorously. This will cause loss of the residue and poor experimental results.Evaporation should occur but not too strong as to cause loss of residue (splattering.) The easiest way to control the heating is by moving the Bunsen burner with your hand.15.Continue to heat the beaker for an additional five minutes.

Note : If the residue starts to melt (glassy appearance), the heating is too strong and the residue had probably been already heated to dryness. Heating is done with the purpose to drive off the gaseous products, and not to melt the residue.Under no circumstances should you heat the residue with a strong flame (crucible bottom is red) for more than 5 minutes.16. Allow the beaker to cool to room temperature17. Determine the mass of the beaker and its contents on the analytical balance assoon as the beaker reached room temperature.Note : If the residue of NaCl is kept for a while in the open air, it will absorb moisture from the air, which will add to the mass of the residue and result in an incorrect final value.

18.Return the beaker and contents to the triangle and reheat the beaker strongly (beaker bottom will turn red) for 3 minutes.19. Allow the beaker to cool to room temperature20.Determine the mass of the beaker and its contents on the analytical balance as soon as the beaker reached room temperature.21.If the mass of the beaker and its contents has changed by more than 1 mg (0.0001 g) from the pervious heating, reheat until a constant mass is obtained.

Storage of chemical reagentsHazard informationHazard classification:Non Hazardous. Non Dangerous Goods.Risk phrases:Not considered a hazard according to the criteria of NOHSC.Safety phrases: Not considered a hazard according to the criteria of NOHSC.First aid measuresSafety showers and eye wash facilities should be provided.

Swallowed:If conscious wash out mouth with water. Seek medical advice. Show this MSDS to medical practitioner.

Eye:Immediately hold eyelids open and flood with water for at least 15 minutes.Obtain medical aid. Show this MSDS to medical practitioner.

Skin:Remove contaminated clothing. Immediately wash skin thoroughly with water and mild soap. Seek medical advice if irritation persists. Show this MSDS to medical practitioner. Launder clothing before reuse.

Inhaled:Remove from contaminated air. Maintain breathing with artificial respiration if necessary.

Fire fighting measures

Suitable Extinguishing MediaWater spray. Carbon dioxide, dry chemical powder, or appropriate foam.

Hazards from Combustion ProductsDecomposition products include oxides of sodium.Precautions For Fire Fighters and Special Protective EquipmentFire fighters and others who may be exposed to combustion products during fire should wear full protective clothing including positive pressure self-contained breathing apparatus (SCBA). Wear SCBA with full face-piece, operated in positive pressure mode when fighting fires.

Accidental Release MeasuresEmergency proceduresPrevent from entering waterways. Restrict access to area. Ventilate area. Remove chemicals that can react with the spilled material.Methods and materials for containment and clean upUse inert material such as sand or earth to contain spill or leak Absorb spills with chemical absorber or vermiculite and dispose of in accordance with local regulations.

Handling and StoragePrecautions for Safe HandlingDo not get in eyes, on skin, on clothing. Avoid prolonged or repeated exposure.

Conditions for Safe StorageStore sealed in original container in a cool well ventilated situation away from foods and other chemicals. Do not store in direct sunlight. Observe good hygiene and housekeeping practices.

Equipment calibration methodsIntroduction to pipette A pipette, pipet, pipettor or chemical dropper is a laboratory tool commonly used in chemistry, biology and medicine to transport a measured volume of liquid, often as a media dispenser. Pipettes come in several designs for various purposes with differing levels of accuracy and precision, from single piece glass pipettes to more complex adjustable or electronic pipettes. Many pipette types work by creating a partial vacuum above the liquid-holding chamber and selectively releasing this vacuum to draw up and dispense liquid. Measurement accuracy varies greatly depending on the style.

Pipette TypesThe main types of pipette in use and the ones we are concerned with are those which transfer precise amounts of fluid on a regular basis in a laboratory environment. These pipettes which can also be called pipets, micropipettes, micro-pipettes or pipettors are predominantly hand held devices, the vast majority of which are of the air-displacement variety.With many advances over the last 50 years (see history of pipettes) in use of materials, laboratory protocols, health & safety requirements and electronics we have seen an evolution in pipettes from many manufacturers.The most common pipettes that require calibration, servicing and maintenance on a regular basis are shown below:

Manual Single Channel Fixed Volumes Pipettes

Manual Single Channel Variable Volume Pipettes (also known as mechanical, adjustable or digital)

Manual Multichannel Variable Volume Pipettes

Manual Single Channel Positive Displacement Pipettes

Electronic Single Channel Variable Volume Pipettes

Electronic Multichannel Variable Volume Pipettes

Pipetting Aids (cell culture pipettes)

What is pipette calibration?

Pipette calibration is a vital element that a good laboratory should consider for any lab regime that requires precise volumes of liquid transfer or dilution.It can be a complex process when all components of the procedure are allowed for a certain possibility, particularly when there are numerous makes and models of pipettes on the market and different calibration protocol options to consider.Pipettes supplied by Fine Care Biosystems hold its individual calibration certificate as per ISO 8655 standards. Calibration of each pipette has been checked at three variable volumes for ten readings.To ensure precision and accuracy of each pipette, regular testing and calibration verification of the instrument is necessary.

Different types of calibration with process overview

Pipette calibration can be carried out in different types and processes. One of the most commonly used methods is gravimetric analysis, where calibration is predominantly undertaken by laboratories as per the standard mentioned in EN ISO 8655 guideline. This method is preferred for traceability to simplicity to a perfect measure.Gravimetric analysis is generally regarded as the economical ways of calibration. Under this method, distributing samples of distilled water is set into a receiving container in an accurate analytical balance. The denseness of water is a known constant, barometric pressure, temperature and humidity are recorded and kept within certain limits and hence Each element of this process is audited itself to ensure compliance and chain of custody for precise calculations.Apart from gravimetric analysis, there are colorimetric methods in use but are often sued for examining pipettes and for non-accredited calibration

How to do pipette calibrationPipettes are necessary equipment often used in chemical laboratories to measure and transfer specific amount of liquid. Pipettes are essentially narrow tube like equipment with a rubber bulb at the top. The tube is numbered from the top to the bottom mostly in increments of ten millimeters. Accuracy in pipette measurement is necessary as any discrepancy in reading can affect the result of chemical reaction. To ensure accuracy it is necessary to perform pipette calibration at regular intervals. Calibration of equipment is desirable even in the most advanced equipment as overtime several factors can affect the readings of measuring equipment. Calibration process helps to check whether or not the equipment is offering correct reading so that it can be rectified in time and efficiency of processes or laboratory test is maintained.Steps :1. Clean the Pipette: Thoroughly clean the pipette as well as the beaker. Dry it out completely. This is done to get rid of any past residue that may affect the results

2. Add Distilled Water: Put some distilled water in an Erlenmeyer flask. Let it stand out on a bench for about 15 minutes. Now, measure the temperature of the water.

3. Beaker Mass Measurement: Find out the mass of the beaker to the nearest tenth of a milligram, using a balance.

4. Taking Help of Pipette Filler: Now, using a pipette filler fill the pipette with the water from the flask. Move this water into the beaker. Weigh the beaker again. Note down the difference in weight of the beaker and calculate the mass of water discharged. Carry out this process three more times.

5.Calculate and determine: Calculate and determine the mean of the four pipette measurements.

6. Adjusting the Buoyancy of Air: Make an addition of 1.06 mg per gram to the mean mass to adjust for the buoyancy of air during the weighing. Do not follow this step in case you are using a digital scale.

7. Calculating Density of Water: Calculate the density of water at the temperature you measured earlier in the process. Determine the mean volume of water discharged by the pipette using the formula: Volume = mass / density

8. Compare Measurements & Calculations: To check the precision of your pipette make a comparison of your measurement and calculations to other results in pipette calibration

RecommendationsTo handle a chemical substance, we should refer to MSDS and use it wisely.Obey the regulation while in the laboratory.Always do the instrument calibration so that it will give correct reading while doing a measurement.