The method of preparing ten millimolar ammonium acetate
Now to prepare ten millimolar (10 dollars\ mM $) ammonium acetate solution, you need to follow the following method.

Prepare clean utensils first, such as volumetric bottles, scales, glass rods, beakers, etc. Weigh an appropriate amount of ammonium acetate solid accurately with the balance. The molar mass of ammonium acetate can be known according to $n = cV $ ($n $is the amount of substance, $c $is the concentration of the solution to be prepared, and $V $is the volume of the solution to be prepared). If you want to prepare 10 dollars\ mM $ammonium acetate solution for $V $liters, the amount of ammonium acetate required is $n = 0.01\ mol/L × V\ L $. From this, the mass of the required ammonium acetate solid is calculated $m = nM $ ($M $is the molar mass of ammonium acetate).

Weigh it out, place it in a clean beaker, add an appropriate amount of distilled water, and slowly stir with a glass rod to fully dissolve the ammonium acetate. After it is completely dissolved, carefully transfer the solution along the glass rod to a pre-washed and calibrated volumetric flask. Rinse the beaker and glass rod several times with a small amount of distilled water, and inject the rinsing liquid into the volumetric flask together to ensure that there is no leakage of solute.

After that, add distilled water to the volumetric flask close to the scale line, and use a rubber head dropper to add water dropwise until the concave liquid level of the solution is tangent to the scale line. Cover the volume cork, shake it upside down repeatedly to mix the solution evenly. In this way, the preparation of ten millimorbidity ammonium moacetate solution is completed.