Which of the following are decomposition reactions? *
1. CH4 (g) + O2(g) → CO2 (g) + H20 (1)
2. Cao (s) + CO2(g) → CaCO3 (s)
3. Mg (s) + O2 (g) – Mgo (s)
4. POCO3 (s) – Pbo (s) + CO> (9)

4

Explanation:

Starts with a compound and breaks down.

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zfoods? ok, pressure is used to keep the heat inside and to keep the food perfect.

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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