At a certain temperature this reaction follows second-order kinetics with a rate constant of 0.974 M/s Suppose a vessel contains H3PO4 at a concentration of .850 M. Calculate how long it takes for the concentration of H3PO4 to decrease by 82%. You may assume no other reaction is important. Round your answer to significant digits.

Achange in the number of neutrons in an atom will change an blank . when the number of protons changes in an atom, a new element will form.

In the following table, all the columns for the element calcium are filled out correctly. element electron structure of atom electron structure of ion net ionic charge calcium 1s22s22p63s23p64s2 1s32s22p63s23p64s1 +1 true false

16. why must the number of electrons lost equal the number of electrons gained in every redox reaction? use 3 – 4 sentences in your own words to address this question. 18. what type of radiation is emitted when chromium-51 decays into manganese-51? show the nuclear equation that leads you to this answer. 19. a radioactive nucleus alpha decays to yield a sodium-24 nucleus in 14.8 hours. what was the identity of the original nucleus? show the nuclear equation that leads you to this answer.