13. How many unpaired electrons are found in NiBr4 2– (tetrahedral)? (A) 0 (B) 4 (C) 1 (D) 5 (E) 2

15. A salt solution sits in an open beaker. Assuming constant temperature and pressure, the vapor pressure of the solution . (A) decreases over time (B) We need to know which salt is in the solution to answer this (C) We need to know the temperature and pressure to answer this (D) stays the same over time (E) increases over time