If the condition change such that there are 4 mil at 4 atm and at 270 K, what is the new volume?

Increases in temperature tend to decrease density since volume will generally increase. There are exceptions however, such as water's density increasing between 0°C and 4°C. Below is a table of units in which density is commonly expressed, as well as the densities of some common materials.

Explanation:

oxygen, selenium, tellurium, and polonium.

they're all from the same group as sulfur (group 16).