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General Chemistry 4th Edition University Science Books presented by Sapling Leam

ID: 556399 • Letter: G

Question

General Chemistry 4th Edition University Science Books presented by Sapling Leaming Mapdab Cryolite, NayAIFs(s), an ore used in the production of aluminum, can be synthesized using aluminum oxide. Balance the equation. Tip: If you need to ciear your work and reset the equation click the button that looks like two red arrows. A1,03(s) + NaOH(l) + HF g) Na,Air,+H20g) If 10.1 kilograms of AlOs(s), 58.4 kilograms of NaoH(0, and 58.4 kilograms of HF (g) react completely, how many kilograms of cryolite will be produced? Number 62.184 kg Na,AlF Which reactants will be in excess? What is the total mass of the excess reactants left over after the reaction is complete? Also, Number NaOH HF 22.83 kg Exit loin ^ Gha l In & View Solution G) Check Answer 0 Next

Explanation / Answer

moles of Al2O3 = mass / molar mass

                         = 10.1 x 10^3 / 101.96

                       = 99.06

NaOH moles = 58.4 x 10^3 / 40 = 1460

moles of HF = 58.4 x 10^3 / 20 = 2920

balanced equation :

Al2O3   + 6 NaOH + `12 HF -------------------> 2 Na3AlF6 + 9 H2O

1                    6              12                                    2

99.06             1460          2920

limiting reagent is Al2O3

excess reagents NaOH , HF

mole of Na3AlF6 formed = 2 x99.06 / 1

                                      = 198.12

mass of Na3AlF6 = 198.12 x 209.94

                            = 41593 g

                            = 41.6 kg

mass of Na3AlF6 formed = 41.6 kg

NaOH remaining = 1460 - 6 x 99.06

                            = 865.64

mass of NaOH = 865.64 x 40

                         = 34626 g

mass of NaOH = 34.63 kg

moles of HF remains = 2920 - 12 x 99.06

                               = 1731.3

mass of HF = 1731.3 x 20

                  = 34626 g

                 = 34.63 kg

mass of excess reagent left = 34.63 + 34.63

                                           = 69.2 kg

mass of excess reagent left = 69.2 kg