Preparation of five millimoles of ammonium acetate
If you want to make five millimoles (5 mM) of ammonium acetate, you must first prepare various utensils and medicines. Refined acetic acid and ammonium hydroxide solutions are required, and accurate measuring instruments such as pipettes and volumetric flasks are required.

Take a clean volumetric flask first, and choose the one that suits its volume depending on the amount of solution required to prepare it. If you want to make a hundred milliliters (100 mL) solution, choose a hundred milliliters volumetric flask.

Take an appropriate amount of acetic acid with a pipette every time. According to the stoichiometry method, the amount of acetic acid in an ammonium acetate solution of five millimoles per liter (5 mM) needs to be accurately calculated. Let the reaction of one molar ratio produce ammonium acetate, that is, the number of moles of acetic acid reacted with ammonium hydroxide is equal. Knowing the molar mass of acetic acid, the mass of acetic acid can be calculated according to the amount of ammonium acetate required, and then converted into volume, which can be carefully measured by pipette.

Then slowly inject into the volumetric bottle. Then use a pipette to measure an appropriate amount of ammonium hydroxide solution, and also take according to the measurement. Add the ammonium hydroxide solution dropwise to the volumetric bottle containing acetic acid, and gently shake the volumetric bottle while adding it to make the two fully react. During this process, it can be seen that there are slight changes in the solution due to acid-base neutralization.

After the two are mixed, dilute them with deionized water. Slowly add water along the inner wall of the volumetric flask, close to the scale line, and use a dropper to carefully drop until the concave liquid level of the solution is tangent to the scale line.

Finally, cap the volume bottle tightly and turn it upside down several times to mix the solution evenly. At this point, the preparation of the five millimolar ammonium acetate solution is completed. When preparing, be careful and measure accurately to obtain the solution of the required concentration for various experiments.