What is the name of the phase where stars live out most of their lives?
interstellar medium
main sequence
equilibrium
accretion

Which are causes of mechanical weathering? check all that apply.oacid raino plant growtho animal actionso carbon dioxideo pressure release

1)each group 16 element has how many valence electrons? ( )4 ( )6 ( )8 ( )16 2)how many dots appear in the dot structure for calcium ion, ca2+? ( )zero ( )one ( )two ( )eight 3) which of the following atoms forms a cation to obtain an octet of outer shell electrons? ( )magnesium ( )oxygen ( )fluorine ( )helium 4) an al3+ ion contains 13 protons and 10 electrons. ( )true ( )false 5) valence and non-valence electrons are represented in lewis dot structures. ( )true ( )false

How many grams of oxygen gas are contained in a 15 l sample at 1.02 atm and 28°c? show your work.