Helium why do some beacons have 18 witnesses and some with only 4

What is the number of atoms in 3.54 mol s

What is the ph of a 0.0010 m hno3? 1.0 3.0 4.0 5.0

13. a covalent bond between two atoms is likely to be polar if: a. one of the atoms is much more electronegative than the other. b. the two atoms are equally electronegative. c. the two atoms are of the same element. d. the bond is part of a tetrahedrally shaped molecule. e. one atom is an anion.