Bob adds heat to a substance. When enough heat is added, A. its particles move closer together and the substance becomes a gas.
B. its particles move farther apart and the substance becomes a solid.
C. its particles move farther apart and the substance becomes a gas.
D. its particles move closer together and the substance becomes a solid.

C. its particles move farther apart and the substance becomes a gas.

Explanation:

A. is wrong because moving closer together creates a solid, not a gas.

B. is wrong because moving father apart creates a gas, not solid.

C. is correct because moving farther apart creates a gas.

D. is wrong because when heat is added particles spread apart because they vibrate faster. Although, in a solid the particles are closer together.

- Just know the states of matter and how the particles move and that will help with this problem.

the number of valence electrons for each molecule or ion is shown beneath the structure. remember hydrogen will not have more than two electrons. this hydrogen is part of a covalent bond (sharing two electrons). a double bond here would cause hydrogen to share four electrons with phosphorus.

answer:

the reaction is type of combination reaction.

explanation:

on the product side, there are 2 molecules of bonded to fe   which means one atom of fe are combined two molecules of . so, balanced chemical equation becomes :

this reaction follows the reaction type of combination reaction. a combination reaction is defined as chemical reaction in which reactants combines together to form a single product.