The weight of anything in any place is
(mass of the thing) x (acceleration of gravity in that place).
-- On Earth, the acceleration of gravity is about 9.807 m/s²
Weight of 19 kg of mass is (19 kg) x (9.807 m/s²) = 186.3 newtons
-- On the Moon, the acceleration of gravity is about 1.623 m/s²
Weight of the same 19 kg of mass is (19 kg) x (1.623 m/s²) = 30.8 newtons