Which tool is most suitable for a chemist to measure the mass of a liquid

The most suitable tool is using a graduated cylinder and a calibrated balance.

Explanation:

To measure the mass of a liquid, first you have to define an specific volume of liquid to measure (example 200 milliliters), then using a graduated cylinder you measure this quantity and put it all on the balance. You read the mass value (example 285 grams). To finish you have to measure the mass of the graduated cylinder empty (example 100 grams) and then subtract it to the weight of the liquid with the calibrated cylinder (example 285 g - 100 g = 185 g).