Balance
The 17-letter word for an instrument used to find mass is "microbalance." A microbalance is a highly sensitive device used to measure the mass of very small objects with high precision. It is commonly used in scientific research and analytical chemistry for accurate weight measurements.
A balance
Carat is used appropriately to measure the weight of gemstones, as pounds, tons or kilos are used to measure the weight of mass.
It is a meterstick!
The word milligram does not have a synonym. Milligram is a unit that is used to measure the mass of an object.
centimeter
The ten letter word in an Anemometer, unless you are thinking of Wind Vane (which is two words)
mass
The mass of an object is a measure of how much matter it contains.
It is a measure of the amount of matter in an object.
The word you are looking for is "mass."