Which of the following will not break down due to a chemical change?
1.h2o
2.ne
3.n2o
4.hf

2. Ne  

Explanation:

Neon is an element. You cannot break down an element by chemical means.

1, 3, and 4 are wrong. They are all compounds, and compounds can be broken down by chemical means.

the old alchemists made significant contributions to science even though there starting premises were off a bit. their conclusions after failure would steer them into better directions for investigation. science is no more than close observation and the initial mistakes result in rethinking and retrying experiments.

the answer is 303.15 or 303