A solid mixture weighing 0.4982 g contained only ferrous ammonium sulfate hexahydrate (FeSO4.(NH4)2SO4.6H2O, 392.13) and ferrous chloride hexahydrate (FeCl2.6H2O, 234.84). After reacting with cupferron and ignition, the sample produced 0.2983 g Fe2O3 (159.69). Calculate the weight percent of Cl in the original sample. (provide complete soln and use gravimetric analysis)

Seoyeon needs to determine the formula of an unknown hydrate (AB-XH2O). Given the following data: mass of empty crucible mass of ABXH2O + crucible mass of AB + crucible 16.5245 g 26.9416 g 21.6515 g Which of the following is the correct formula of the hydrate? (The molar mass of AB is 120.37 g mol-1) A) AB-7H2O B) AB-H20 C) AB-5H2O D) AB-3H2O

A 19.51 g sample of impure methylamine, which contains 72.58% (by mass) of CH;NH: , is reacted with 30.81 g of pure oxygen gas: 2.1 4CH, NH,(2) + 90,(8) - 4C0,(8) + 10H,0(?) + 2N;(8) 2.1.1 What is the percentage yield of this reaction if 5.54 g of nitrogen gas is collected? 2.1.2 In another experiment, this impure methylamine was used as follows: • An unknown mass of the impure compound is dissolved in enough water to make 500.0 m of solution. • 20 ml of this solution was transferred by pipette to a clean 250 ml volumetric flask and made up to the mark. • The molarity of the CH;NH; in the final solution was determined to be 0.103 M. Determine the mass of CH;NH; present in the original amount of impure compound used make this solution.

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