Which one of the following changes would cause the pressure of a gas to double assuming temperature was held constant?
1. decreasing the volume of a gas from 4.0 l to 2.0 l while keeping the moles the same.
2. increasing the volume of a gas from 2.0 l to 4.0 l while keeping the moles the same.

1. Decreasing the volume of a gas from 4.0 L to 2.0 L while keeping the moles the same.

Explanation:

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.