Problem: I forget to tare my flask.
Solution: For all of your flasks, write the weight twice on the inside of the joint in pencil. The pencil will eventually rub off, but since the tare is written twice, having one blur is no problem. Then you can erase the other and re-tare, so the weight is always accurate.

Problem: I need to weigh 0.5 mg of catalyst. The balance is not accurate for such small weights.
Solution: Make a solution of (say) 5 mg of the solid in (say) 1 mL of solvent, and then syringe out 100 microliters.

Problem: I do not know the density of a liquid- how do I know how much to add via syringe?
Solutions:
- Weigh an empty syringe, fill the syringe (start by assuming the density is 1g/mL), and weigh again. Adjust until the weight is accurate.
- Measure the density of the liquid by weighing a known volume and doing the appropriate division
- For small amounts of viscous liquids, weigh an empty pipette, dip the tip in the substance, and weigh again.

Problem: When I try to use a syringe to measure a certain liquid, nothing happens because it is too viscous to be drawn into the syringe.
Solutions:
- Dilute the liquid with your reaction solvent, and then try using a syringe.
- For small amounts of viscous liquids (<20 mg), weigh an empty pipette, dip the tip in the substance, and weigh again.
- For larger amounts of viscous liquids (contributed by Ivan Zhyvolup): Take your sample vial (standing in a beaker), put on scale, tare, then withdraw the required weight using the negative reading as a guide. For example, to withdraw 100 mg, get the scale to read -100 mg.

Problem: I have a small amount of an oil (say, 40 mg) in a flask. I only want to use some of it (say 10 mg), but I do not know how to weigh it accurately.
Solution: For the example given, dissolve the material in 4 mL of solvent, and remove 1 mL. You can remove the solvent to check the weight. This method is more accurate than you might think.

Problem: I want to weigh a hygroscopic solid, but it "melts" as I weigh it, and then I can not easily tranfer it to my reaction.
Solutions:
- Weigh the reagent in a glove box, if one is available.
- Weigh the reagent directly into your reaction flask, if practical.
- Weigh the reagent in a glass vessel, and then dissolve it in an appropriate solvent for transfer.

Problem: I want to weigh a reagent with a melting point near room temperature. It keeps changing states on me- it clogs a syringe, but melts on weighing paper! (t-BuOH is one example).
Solution: Warm it up slightly (if it is heat- stable) and syringe quickly, before it cools enough to solidify.

Problem: I want to syringe a liquid that evaporates at room temperature, and I never get an accurate volume.
Solution: Cool it to a low temperature before syringing it.