Question

Instrument used to find mass
_ _ _ _ _ _ - _ _ _ _ _ _ _ _ _ _ _ ?

Answer 1

i don't know, a scale really, their is no such thing as a massometer, and although it doesn't fill the blanks, a spectrometer does too

Answer 2

A balance. As I've written a number of times, farmers weigh a sack of potatoes on a scale. In the laboratory we use a balance.