Assuming the compound is dissolved in water what is the formula for phosphorus acid?
A. H3P
B. H3PO4
C. HP
D H3PO3

The number to the right of an element's symbol (ex. c-12) identifies the of an isotope.

The bond energy for the van der waals bond between two helium atoms is 7.9×10−4ev. assuming that the average kinetic energy of a helium atom is (3/2)kbt, at what temperature is the average kinetic energy equal to the bond energy between two helium atoms

The chemical equation below shows the reaction of sodium (na) and chlorine (cl) to form sodium chloride (nacl). 2na + cl2 → 2nacl in this equation, which of the following is a reactant? i. sodium ii. chlorine iii. sodium chloride