hel. which of the following statements regarding physical and chemical changes is true? a. both physical and chemical changes alter the atomic structure of a substance. b. neither physical not chemical changes alter the atomic structure of a substance. c. physical changes alter the atomic structure of a substance, while chemical changes do not. d. chemical alter the atomic structure of a substance, while physical changes do not. hur

At a temperature of 393 k, the temperature of a sample of nitrogen is 1.07 atm what will the pressure be at a temperature of 478 k

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

A1.5l container holds p.50 grams of an unknown gas at a pressure of 0.44 atm and a temperature of 50.c what is the molar mass of the unknown gas