Which group of lists below is made up of only pure substances? Homogeneous mixtures, heterogeneous mixtures, compounds

What is the empirical formula of vanadium 1 oxide given that 20.38 grams of vandium combines with oxygen to form 23.58 grams of the oxide

Which of the following true? a_volcanoes and earthquakes often near the plate boundaries. b_volcanoes occur whereve there are tall mountains. c_earthquakes cause volcanoes in the same location to erupt violently d_volcanoes and earthquakes occur only where plates are colliding with each other

Why are the trends and exceptions to the trends in ionization energy observed?