The elements X and Y have spectra pictures as shown in the diagram below. W is the spectrum of a mixture of elements X and Y and a third element, Z. Use the diagram of the spectrum pictures to answer any questions that follow. Which diagram contains the spectra for elements X and Y?
A
I

B
II

C
III

D
IV

Does anyone know a lot about how to: - calculate mass of magnesium metal - calculate the actual yield of magnesium oxide - calculate the theoretical yield of mgo - calculate the percent yield of mgo - determine the percent yield of mgo - determine the average percent yield of mgo i had to do an online lab and its asking these questions but i have no idea where to start or how to be able to find these things. i can post the chart of the data from the lab or if you can tell me exactly how i can find each.

Compare the valence electron configuration of the nobles gas elements seen here. what statement is correct?

In 1901, thomas edison invented the nickel-iron battery. the following reaction takes place in the battery. fe(s) + 2 nio(oh)(s) + 2 h2o(l) fe(oh)2(s) + 2 ni(oh)2(aq) how many mole of fe(oh)2, is produced when 5.35 mol fe and 7.65 mol nio(oh) react?