Anhydrous CoCl2 is blue; CoCl2•6H2O is red. When CoCl2•6H2O is heated and water is clearly being driven off, it becomes uniformly violet before turning blue. How can this be explained?

If anyone would be able to me out with these three questions it would be these are from the chem 2202 course.

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.

What is the wavelength of a 3*10^12 hz infrared wave a 3*10^20m b 1* 10^4m c 3*10^-3m d 1*10^-4 m