Phosphorus is obtained primarily from ores containing calcium phosphate. if a particular ore contains 66.1% calcium phosphate, what minimum mass of the ore must be processed to obtain 3.53 kg of phosphorus?

Which type of substance ionizes partially and gives off hydrogen ions when dissolved in water? a. strong acid b. strong base c. weak acid d. weak base

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

Imagine that you push on a large rock. at what point does your effort change the rock’s mechanical energy?