Answer:
oxygen is an element because it is a pure substance which cannot be split into simpler substances by chemical means
There chemical reactions that can realise or absorb gas to the atmosphere. This means it is harder or impossible to measure it with normal weighing devices and normal taring equipment. As a principal in chemical reactions we have conservation of mass.
Answer:
C.) 35
Explanation:
The mass is made up of the total protons and neutrons in an atom. Protons and neutrons both have a mass of 1 amu. Electrons are not included in this measurement because they have an insignificant mass (practically 0).
(17 protons x 1 amu) + (18 neutrons x 1 amu) = 35 amu
Therefore, if an atom contains 17 protons and 18 neutrons, the mass should be 35 amu.
The best answer choices can be A.because it reduction he eletrolytic from positive