Asample of hydrated calcium sulfate has a mass of 2.643 g. after dehydration, the sample has a mass of 2.090 g. what is the percent by mass of water in the hydrate?

How many molecules are found in 1.32 mol of nacl?

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

Which best explains why an iceberg floats?