you start with 12.94 g sample of a mixture containing sio2, nacl, and nh4cl. if after subliming
away the nh4cl, you have 2.17 grams of sample remaining, what was the mass percent of nh4ci
in the original sample? show all work.

83.23 %

We are given;

We are required to get the mass percent of NH₄Cl in the original sample

Mass of NH₄Cl = Total mass of the mixture - remaining mass after sublimation

                         = 12.94 g - 2.17 g

                          = 10.77 g

% of NH₄Cl by mass =(Mass of NH₄Cl÷Total mass of original sample)×100

                                  = (10.77 g ÷ 12.94 g) × 100

                                  = 83.23 %

Therefore, the percent by mass of NH₄Cl in the original sample is 83.23%

first one is the correct answer

nacl is added to the aqueous of what? ? in order to get a proper answer you have to specify the exact composition of the aqueous solution.