What is the mass of one mole of Cl2

What is a spectator ion in the reaction between ba(no3)2(aq) and (nh4)3po4(aq)?

What is common about these molecules? a. their atoms are held together by covalent bonds. b. they are all made up of the same two atoms. c. their atoms are held together by ionic bonds. d. they are all made up of oxygen atoms only.

Which of the following are good traits of a hypothesis? it will be able to be testedit can predict an outcomeit will explain the observationsall of these