19. cerium is the most abundant rare earth metal. pure cerium ignites when
scratched by even a soft object. it has four known isotopes: "ce (atomic mass
= 135.907 amu), ce (atomic mass = 137.905 amu), 4°сe (atomic mass =
139.905 amu), and "ce (atomic mass = 141.909 amu). ce-140 and ce-142 are
fairly abundant. which is the more abundant isotope?

idk

explanation:

a pan containing water is placed in a positio n where it is exposed to a 10 mile per hour wind. the pan contains a uniform depth of 1.27 cm of water, is quite wide, and has a length of 2.44 m in the wind direction. the water in the pan is at a constant temperature of 15.5 °c.

metric time was an attempt to create a standard unit of time based off of 10, but it never took off an is not included in the metric system (si)