How many grams of a stock solution that is 87.5 percent h2so4 by mass would be needed to make 275 grams of a 55.0 percent by mass solution?

(urgent)

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

In apex! a liquid heated beyond a certain temperature becomes

Which of the following are correct values for the ideal gas laws constant r