Question #eda23

The balanced chemical equation that describes this synthesis reaction looks like this

#color(blue)(2)"Na"_ ((s)) + "Cl"_ (2(g)) -> color(purple)(2)"NaCl"_ ((s))#

The thing to remember here is that the coefficients that are added to each chemical species that takes part in a reaction represent number of moles.

This means that the ratios that exist between these coefficients represent the ratios that must exist between the moles of each chemical species that takes part in the reaction.

In this case, you know that regardless of how many moles of sodium metal react, the reaction will produce the same number of moles of sodium chloride.

That is the case because you have a #1:1# mole ratio between the two

#(color(blue)(2)color(white)(.)"moles Na")/(color(purple)(2)color(white)(.)"moles NaCl") = color(blue)(1)/color(purple)(1)#

Now, if you assume that you have enough moles of chlorine gas to allow for all the moles of sodium metal to react, you will have

#4 color(red)(cancel(color(black)("moles Na"))) * (color(purple)(2)color(white)(.)"moles NaCl")/(color(blue)(2)color(red)(cancel(color(black)("moles Na")))) = color(darkgreen)(ul(color(black)("4 moles NaCl")))#