Changing a chemical property of a substance never alters its chemical composition.
always alters its chemical composition.
will only alter its chemical composition if the change is small.
will only alter its chemical composition if the change is large.

A chemical change in a substances always alters the chemical composition.

Explanation:

Molecules always are combined to create a new substance, otherwise it would only be a physical change and the substance would have still had the same molecular design.

i just calculated it all out, and not including weekends, and all the different days off. as of this school year (2018-2019) students are spending 2198 hours in school this year

answer:

the answer is 6 valence electrons.

explanation:

valence is the # of electrons on the outer most shell of an atom.

oxygen has 6.

although, the valency of oxygen is 2, because it only needs to make 2 covalent bonds, or gain 2 electrons, to achieve the stable octet configuration of a noble gas.

that's it!

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~ trueboss72