Chemical experiment report format

Example 1 Quantitative Analysis Experimental Report Format

Experimental title: Determination of h2c2o4 content in oxalic acid
Learn the preparation, calibration and use of the relevant equipment of naoh standard solution;
Learn the use of basic burettes and practice titration.
Experimental principle:
H2c2o4 is an organic weak acid with ka1 = 5.9 x 10-2 and ka2 = 6.4 x 10-5. For the analysis of the constant components, cka1>10-8, cka2>10-8, ka1/ka2<105, the two-step dissociation h+ can be titrated in the aqueous solution at one time:
H2c2o4+2naoh===na2c2o4+2h2o
The measuring point ph value is about 8.4, and phenolphthalein can be used as an indicator.
The naoh standard solution is obtained by indirect preparation and is calibrated with potassium hydrogen phthalate:
-cook
-cooh
+naoh===
-cook
-coona
+h2o





The reaction metering point has a pH value of about 9.1, and phenolphthalein can also be used as an indicator.
experimental method:
I. Preparation and calibration of naoh standard solution Weigh naoh1g in a 100ml beaker with a tabletop balance, add 50ml of distilled water, and stir to dissolve. Transfer to a 500 ml reagent bottle, add 200 ml of distilled water, and shake well.
Accurately weigh 0.4~0.5g three parts of potassium hydrogen phthalate, place them in a 250ml Erlenmeyer flask, add 20~30ml distilled water to dissolve, add 1~2 drops of 0.2% phenolphthalein indicator, titrate with naoh standard solution to The solution is reddish and the end point is not faded for half a minute.
Second, h2c2o4 content determination Accurately weigh about 0.5g oxalic acid sample, placed in a small beaker, add 20ml of distilled water to dissolve, and then quantitatively transferred to a 100ml volumetric flask, dilute to the mark with distilled water, shake.
Pipette the sample solution into a conical flask with a 20 ml pipette, add 1~2 drops of phenolphthalein indicator, titrate with naoh standard solution until the solution is reddish, and the end point is not faded for half a minute. Do it three times in parallel.

Recording and processing of experimental data:
First, the calibration of naoh standard solution experiment number 123 remarks
Mkhc8h4o4 /g start reading

Final reading
Result
Vnaoh /ml start reading
Final reading
Result
Cnaoh /mol·l-1
Naoh /mol·l-1
Relative average deviation of results



Second, h2c2o4 content determination experiment number 123 remarks
Cnaoh /mol·l-1





m sample /g
v sample /ml20.0020.0020.00
Vnaoh /ml start reading
Final reading
Result
Ωh2c2o4
H2c2o4
Relative average deviation of results


Experimental results and discussion:
......

in conclusion:


Example 2 Synthesis experiment report format Experiment title: Synthesis of ethyl bromide
Experimental purposes: 1. Learn the principle and method of preparing ethyl bromide from alcohol
2. Consolidate the operating techniques of distillation and learn to use the separatory funnel.
Experimental principle:
The main side reaction:
Reaction device schematic:

Experimental steps and phenomenon records:
Experiment step record
1. Adding:
9.0 ml of water was added to a 100 ml round bottom flask, and while cooling and shaking were continued, 19.0 ml of concentrated sulfuric acid was slowly added. After cooling to room temperature, 10 ml of 95% ethanol was further added, and then 13.0 g of finely divided sodium bromide was added under stirring, and then 2-3 zeolites were charged.
The heat is released and the flask is hot.
2. Assembly device, reaction:
Assemble the distillation unit. To prevent loss of product volatilization, 5 ml of 40% nahso3 solution was added to the receiver, cooled in an ice water bath, and the end of the receiving tube was just immersed in the aqueous solution of the receiver. Heat the flask on the asbestos net with a small fire, the material in the bottle begins to bubble, control the size of the flame, and gradually distill the oily substance. After about 30 minutes, slowly increase the flame until no oil drops are distilled out.
The heating started and a white mist hbr appeared in the bottle. Later, the white mist hbr increased in the bottle. The original insoluble solid in the bottle gradually dissolved, and the solution was orange-yellow due to the formation of bromine.

3. Product rough score:
Pour the liquid from the receiver into the separatory funnel. After standing to separate the layers, the lower layer of crude ethyl bromide was placed in a small, dry conical flask. The conical flask was immersed in an ice water bath to cool, and concentrated sulfuric acid was added dropwise to the bottle while shaking until the ethyl bromide became clear and transparent, and the liquid layer was separated at the bottom of the bottle. The lower sulfuric acid layer was carefully separated by a dry separatory funnel, and the ethyl bromide layer was poured from the upper portion of the separatory funnel into a 30 ml distillation flask.

The liquid in the receiver is a turbid liquid. The separated ethyl bromide layer was a clear liquid.
4. A distillation unit for the purification of ethyl bromide, adding 2-3 zeolites, heating in a water bath, and distilling off the ethyl bromide. Fractions at 37-40 ° C were collected. The receiver for collecting the product should be cooled with an ice water bath. Colorless liquid, sample + bottle weight = 30.3 g, wherein the bottle weighed 20.5 g and the sample weighed 9.8 g.
5. Calculate the yield.
Theoretical yield: 0.126 × 109 = 13.7g
Yield: 9.8/13.7=71.5%

Results and discussion:
The orange yellow in the solution may be caused by bromine in the by-product.
In the last step, when the ethyl bromide is distilled, the temperature is too high, causing the bromine ethane to escape, and the yield is thus low, and the experiment should be strictly performed in the future.


Example 3 Nature experiment report format experiment title:
Purpose:
experimental method:
Experimental methods and steps phenomena interpretation and chemical reaction






in conclusion:
......
Thinking questions:
......