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An electron in a hydrogen atom relaxes to the n = 3 level, emitting light with a wavelength of 1281nm. What is the value of n for the level in which the electron originated? En = -2.18×10-18/n2 J Or you may use the following equation: Ephoton = 2.18×10-18 (1/n12 – 1/n22) J,  (n1 < n2)   Mark your answer next to words "Final answer is". You must follow significant figure rules.   You must show your work here to receive any credit (you may receive 0 points for only showing your final answer).

Two samples of a compound containing elements A and B were decomposed. The first sample produced 15 g of A and 39 g of B.  The second sample produced 35 g of A and what mass of B?

An unknown element has two naturally occurring isotopes with masses 18.00 amu (A) and 21.00 amu (B) and has an atomic mass of 18.90 amu.  What’s the natural abundance of isotope A (%)?  Mark your answer next to words “Final answer is”. You must follow significant figure rules.   You must show your work here to receive any credit (you may receive 0 points for only showing your final answer).

Choose the ground state electron configuration for Co3+.    

A solid gold cube contains 1.33×1029 atoms.  What is the volume of the cube in cm3? The density of gold is 19.3 g/cm3. Mark your answer next to words “Final answer is”. You must follow significant figure rules.   You must show your work here to receive any credit (you may receive 0 points for only showing your final answer).

What is selection in the context of animal breeding?

A greater probability of detection can be achieved with progeny and recessive gene frequency in the test mates.

What are the two basic tools of animal breeders?

If you have a weak correlation between two traits, what should you expect?

What are the three basic aspects of correlation?