Solution preparation and dilution experiment report?

Preparation of experimental solutions.

1. Purpose of the experiment 1: To grasp the quantity and concentration of the substance.

The general method, steps and various instruments required for preparation 2, preliminary learning of pipettes, pipettes, volumetric flasks.

How to use: 2. Experimental supplies and instruments: scales, beakers, glass rods, graduated cylinders or measuring cups (50ml), droppers, pipettes (5ml and 10ml ml pipettes, volumetric flasks (50ml, 100ml), ear wash balls, corner spoon medicines

Solid sodium chloride, concentrated hydrochloric acid.

1mol l sodium lactate solution, medicinal alcohol ( b = 3, experimental content and experimental procedure (1) preparation of solution 1, preparation of mass concentration solution: preparation b = 9g l sodium chloride solution.

50ml (1) calculated. Calculate the number of grams of solid NaCl required to prepare 50 ml of 9 g of LNaCl solution. (2) Weighing.

Weigh the desired NaCl in a tray and place it in a 50 ml beaker. Dissolve. Take 20ml of distilled water with a graduated cylinder.

Pour into a beaker and stir with a glass rod to completely dissolve the NaCl. (3) Transfer. The NaCl solution in the beaker is drained into a 100ml graduated cylinder with a glass rod, and the beaker is washed 1-2 times with a small amount of distilled water, and the washing solution is injected into the graduated cylinder.

4) Volume. Continue to add distilled water to the graduated cylinder, and when it is close to the 50ml scale mark, use a dropper to add distilled water dropwise until the bottom of the solution concave surface is tangent to the 50ml scale mark. Stir well with a glass rod to obtain 50 ml of 9 g of LNACL solution.

Pour the prepared solution into the designated ** bottle. 2. Preparation of the amount and concentration solution of the substance: 100ml of hydrochloric acid is prepared with concentrated hydrochloric acid (1) calculation.

Calculate the mass fraction required to prepare 100ml of solution.

wb = density density = number of milliliters of concentrated hydrochloric acid.

Preparation of a solution for chemical experiments.

Purpose of the experiment.

1. Practice preparing a solution with a certain concentration of substance.

2. Deepen the understanding of the concept of quantity concentration of substances.

3. Practice the use of volumetric flasks and burettes.

Experimental principle. The concentration of solute substances refers to the amount of solute substances contained in a certain volume of solution, and the unit is: mol l (mol liters), definition:

Quantity concentration of a substance (c) = Amount of solute substance (n) Volume of solution (v).

Laboratory supplies. Drugs: NaCl, distilled water.

Instruments: beakers, acid burettes, volumetric flasks (100ml), rubber tip droppers, graduated cylinders, glass rods, medicine spoons, filter paper, tray balances.

Doubts and difficulties. 1 How should NAOH solids be weighed?

Weigh it in increments. First take a clean small beaker, weigh the mass on the balance, then adjust to add the number of masses to be weighed NaOH, and add solid hydroxide gas to the small beaker until the balance is balanced.

2 Use of volumetric flasks.

Volumetric flasks are thin-necked, pear-shaped, flat-bottomed glass bottles with ground glass stoppers or plastic stoppers at the top of the bottle. Volumetric flasks are often used to prepare solutions with an accurate volume. The volumetric flask is marked with temperature and volume, indicating that at the indicated temperature, when the concave surface of the liquid is tangent to the scale of the volume bottleneck, the volume of the solution is exactly equal to the volume marked on the bottle.

There are many kinds of commonly used volumetric flasks, such as 100ml, 250ml, and 1000ml. The stopper of the volumetric flask should be tied to the neck of the bottle with a strong string to prevent damage or loss. Before using the volumetric flask, it is necessary to check whether it is in good condition and whether there is water leakage at the mouth of the bottle.

Here's how to check it: Add a certain amount of water to the bottle and plug the cork. Press the cork with your index finger and hold the bottom of the bottle with your other hand, turn the bottle upside down and observe if there is any water leaking around the cork.

If there is no leakage, put the bottle upright and rotate the stopper 180 to plug it tightly, still turn the bottle upside down, and then check whether there is water leakage. Only volumetric bottles that have been inspected for non-leakage can be used. When using a volumetric flask to prepare a solution, if it is a solid reagent, the weighed reagent should be dissolved in a beaker with an appropriate amount of distilled water before being transferred to a volumetric flask.

If it is a liquid reagent, the required volume of liquid should be transferred to a beaker first, diluted with an appropriate amount of distilled water, and then transferred to a volumetric flask. Special attention should be paid to significant calorific changes during dissolution or dilution, and the temperature of the solution must be restored to room temperature before it can be transferred to the volumetric flask. After the volumetric flask is used, it should be washed and dried (the glass frosted cork should be padded with a paper strip at the cork and the bottle mouth to avoid the bottle stopper and the bottle mouth from sticking).

Objective 1 Learn to use calibrated standard solutions to determine the content of unknowns 2 Familiarize yourself with the use of pipettes and volumetric flasks to consolidate titration operations.

1. Question 1 What are the precautions for the operation of alkaline burettes? 2 Why can sodium hydroxide standard solution be used to accurately determine the acetic acid content?

2. Explanation 1 Principle 2 In the process of titration to close to the end point of the titration, there should be deionized water to wash the inner wall of the Erlenmeyer flask, but do not do this often during the titration process, otherwise, the volume of the liquid in the Erlenmeyer flask is too large, affecting the accuracy of the measurement results. 3 Review the operation of the volumetric flask. 4 Operation Notes(1) The volume should be accurate, and it must be shaken well after the volume is fixed.

After shaking, do not add water when the liquid level is inconsistent with the scale mark. (2) When pipetting is accurate, when transferring the solution from the pipette to the volumetric flask, stop for 15 seconds before removing the pipette after the solution is fully discharged.

3. The experimental results will be judged by receiving the unknown solution from the experimental teacher, and the experimental teacher will provide standard data. Excellent: Medium, pass, fail, relative error: 4mg, 4mg-8mg, 8mg-12mg, 12mg-20mg, >20mg

It is recommended that the "Solution Preparation Experiment Report" contain the following contents:

1).The name of the experiment report.

2).The purpose and requirements of the preparation solution.

3).The name, quality specification, origin, and batch number of the solute and solvent used in the preparation.

4).The name and specification of the instrument used in the preparation.

5).The amount of solute and solvent required for preparation (mass, volume) and the calculation process.

6).Briefly describe the specific process (including bottling and labeling).

7).The operating environmental conditions of the place where the solution is prepared, such as temperature and humidity values.

8).Personally, I think there may be an existing problem.

9).The name (signature) of the preparer and the name (signature) of the reviewer during the operation process.

10).The name of the unit and department of the preparer and reviewer.

11).The specific date and place of preparation of the solution.

12).Name of the receiving unit of the solution preparation experiment report.

Preparation of a solution for chemical experiments.