Preparation of a Standard Solution of Sodium Carbonate: Lab Report

September 28, 2017 September 1st, 2019 Free Essays Online for College Students

Making a Standard Solution of Sodium Carbonate

Outline of procedures: to prepare a standard solution of sodium carbonate and carry out a series of titrations to determine the concentration of hydrochloric acid.

Standard solution experiment

Finding the concentration of a chemical

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A solution of known concentration is called a standard solution.

Hazardous substances being made or used.

Nature of hazards

Quantities being used

Control measures and precautions

Sodium carbonate

Hydrochloric acid

Irritant

corrosive

2.65g

small

Wear goggles

Wear lab coat and goggles.

Any non-chemical hazards and precautions to be taken

Any spills to be wiped immediately

Disposal of residues.

Done by Technician

Apparatus:

* balance

* weighing bottle

* spatula

* beaker

* glass rod

* wash bottle

* filter funnel

* volumetric flask

* pipette

* teat pipette

* conical flask

* burette

Method

To prepare a standard solution first I will calculate the mass of solute needed. Then I will carefully weigh out the mass of solute, dissolve it into the water and transfer the solution into a volumetric flask. This is a flask of known volume. When the level of liquid in the flask reaches the graduation mark on the neck of the flask I will know the volume of the liquid in the flask. I will then add distilled water to top off the solution to the graduation mark.

A standard solution can only be made from a pure solid which is stable in air therefore I will have to make a solution of sodium hydroxide and then find its concentration. I will do this by titrating it against an acid of known concentration.

Also you cant make a standard solution of hydrochloric acid as when you open the bottle hydrogen chloride escapes into the air so I will have to find the concentration of HCL by titrating it against a standard alkali.

The steps I will take to complete this experiment are as follows.

Measurements

1:

To make 250cm3 of 1.00mol/l solution of sodium carbonate I will use the following measurements:

Mass of 1.00 mol of Na2CO3 = 106g

Mass of Na2CO3 needed to make 1.00 l of a 0.100mol/l solution = 10.6g

Mass of Na2CO3 needed to make 250cm3 of a 0.100mol/l solution = 2065g

2:

Mass of weighing bottle = 9.277g

Calculated mass of anhydrous sodium carbonate = 2.65g

Mass of weighing bottle + solid = 11.93 g

3:

(i) With a clean dry spatula I added anhydrous sodium carbonate to the weighing bottle using a top pan balance until the weighing bottle and contents reached the combined mass that I had calculated.

(ii) I then poured 100cm3 of distilled water into a clean beaker and carefully tipped the sodium carbonate into the beaker.

(iii) I then used a wash bottle to wash out all the solids out of the weighing bottle and then stirred the contents of the beaker using a clean stirring rod until all the solids had dissolved.

(iv) I then poured the contents of the beaker into the volumetric flask using a filter funnel and pouring it down the glass rod to avoid splashing.

(v) I then used a wash bottle to wash out any remaining solution out of the beaker and poured it into the volumetric flask. I then used a teat pipette to add distilled water to make the solution reach the graduation mark before putting the stopper on it and shaking it gently.

4:

(i) I poured the solution into a conical flask and added three drops of indicator.

(ii) I then measured 25cm3 of hydrochloric acid using a pipette and then slowly poured it into the conical flask which already contained the sodium carbonate solution I had made earlier and indicator.

(iii) I stopped when the solution turned pink and measured the level of HCL left in the pipette.

(iv) Then repeated these steps three times to get a fair result

Trial

2

3

Average

Final burette reading

21.50cm3

20.90cm3

21.10cm3

Initial burette reading

0.00cm3

0.00cm3

0.00cm3

Titre

21.50cm3

20.90cm3

21.10cm3

21.00cm3

Results

Na2CO3 + 2HCL –> NaCl + H2O + CO2

Mols of Na2Co3 = 0.0025

Ratio = 1:2

Mols of HCL = 0.005

Concentration of HCL = 0.238mols/dm3

Standard solution of sodium carbonate: Conclusion

In this experiment, I was able to find out the concentration of a chemical through many experiments.

This experiment was carried out under conditions similar to those in an industrial process but there were a couple of differences which include the number of chemicals available to us which hampered our chances of experimenting with different types of chemicals. I think this experiment was a success because I achieved my goal and learned a lot from it.

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