Which part of the following descriptions of a compound or element refers to its physical properties and which to its chemical properties? a. calcium carbonate is a white solid with a density of 2.71 g/cm3. it reacts readily with an acid to produce gaseous carbon dioxide. b. gray powdered zinc metal reacts with purple iodine to give a white compound.

Aballoon inflated with three breaths of air has a volume of 1.7 l. at the same temperature and pressure, what is the volume of the balloon if five more same-sized breaths are added to the balloon? a balloon inflated with three breaths of air has a volume of 1.7 l. at the same temperature and pressure, what is the volume of the balloon if five more same-sized breaths are added to the balloon?

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 of the following is not an assumption that scientists must make about the natural world? a. regularity b. causality c. predictability d. plausibility