Question

i have no idea how to do this...

192 EQUIPMENT and CHEMICALS • wire gauze • 250-ml beaker - watchglass • alum, KAl(SO4)2-12H20 • unknown hydrate samples S PROCEDURE A. Percentage of Water in Alum Hydrate 1. Weigh a clean, dry, 250-ml beaker covered with a watch glass. Add about 0.8-1.2 g of alum hydrate into the beaker, and reweigh accurately. 2. Support the beaker and watchglass on a ring stand using a wire gauze (Figure 1). Heat the hydrate gently, and you should observe moisture on the sides of the beaker and bottom of the watchglass. Continue heating until all the moisture is evaporated, When the hydrate is completely decomposed, it will change from crystalline to powder. Note: If the watchglass is not completely dry, hold it carefully with crucible tongs over a low burner flame until no moisture remains. 3. Turn off the burner, and allow the beaker to cool for 10 minutes. Carefully transfer the beaker with the watchglass to the balance. Weigh the mass of the beaker, watchglass, and anhydrous compound. 4. Discard the decomposed alum and clean the beaker. Perform a second trial with alum hydrate. Calculate the percentage of water in the hydrate for each trial and the average value. B. Percentage of Water in an Unknown Hydrate 1. Obtain an unknown hydrate from the Instructor, and record the unknown number. 2. Repeat steps 1-4 as in Procedure A, and report the average percentage of water in the unknown hydrate. C. Water of Crystallization in an Unknown Hydrate 1. Given the molar mass of the anhydrous compound from the Instructor, calculate the water of crystallization. The Instructor may wish to verify the experimental percentage of water before giving the molar mass of the unknown hydrate. Note: It is not unusual for the water of crystallization value to differ by a few tenths from a whole number, for example, 2.1 or 6.7. However, the water of crystallization must be rounded to a whole number. In this example 21 is rounded to 2 and 6.7 is rounded to 7. Analysis of Alum

Answer 1

as + mans of o aukyanoas) - (mars of beakert te the formula to calculate - % 8 water in K ACC004), 12760 = mare a water X 100 mais of kallsoa), 120 “) илм а «кисии муалаt = (олох - оос 1 см аtолл + a hydrale)-(mans of bealder+ watch glay . mars of anhydrous compound = (mars y neater - Walerglerst. us) - Watchgears) (0) nous fwater = (wars before heating) - man ofter heating (o) water of crystallization = mass of water X 100 Total wars of compound ? (Kheccod), 1917, 0 (O) Skor Theoritical mas is calculated by:- The ortical mass = (moles of und x mocompounds compound 1 where the pampered x molar mais Poepood unknown her drate water in 0 his given mais of hyarate = mais before heating) - (Mars after reating). no me experimental percentage j woder in nyciate mans of water x 100 Total mars of compound (o) for calculating formula of hy chate a) we mais of water left the compound b) convent it to moles C) convell mars farby arali left into moles d) find natio of water analydrate mole nato @ the mole ratio to calculan formula (0)" water on crystallisation - mans of water I crystallization xlor melar mans of compound