A5.0 - gram sample of zinc and a 50.-milliliter sample of hydrochloric acid are used in a chemical reaction. which combination of these samples has the fastest reaction rate?
1. a zinc strip and 1.0 m hcl (aq)
2. a zinc strip and 3.0 m hcl (aq)
3. zinc powder and 1.0 m hcl (aq)
4. zinc powder and 3.0 m hcl (aq)

What does hund's rule state? a. an orbital can contain two electrons only if the electrons have opposite spins. b. an orbital can contain two electrons only if all other orbitals at that sublevel are empty. c. an orbital can contain two electrons only if the electrons have different energy levels. d. an orbital can contain two electrons only if all other orbitals in that sublevel contain at least one electron.