Question

4o UNKNOWN NUMBER Data Trial 2 Trial 1 ২৪.6.209 30.2449 30.3309 30 398 Mass of the crucible and cover &&.4369 Mass of crucible, cover and sample 7989 Mass of crucible, cover and salt after first heating Mass of crucible, cover and salt after second heating &.99 Mass of crucible, cover and salt after third heating Calculations CaSOu CesOy Chemical formula of anhydrous salt (given) 21149 1.6989 9-689 Mass of hydrate (sample) Mass of anhydrous salt 04169 Mass of water liberated 19-68 g0.44-1 Percentage H20 in the hydrate go -32% 29-56% Percentage anhydrous salt in the hydrate 0.584 mal J. 14 mol Moles of anhydrous salt in 100 g of hydrate 109 mo Moles of water in 100 g of hydrate 95mol Moles of water per mole of anhydrous salt 2 males Average Moles of water per mole of anhydrous salt Casoyn 2H20 Formula of the Hydrate

Answer 1

Potassium aluminium sulfate is commonly encountered as the dodecahydrate.

Molarmass of KAl(SO4)2.12Hzo is474.3884 g/mol Molar mass of KAL (504)z is 258.2050 gmol Molar mass of H20 is 18 glmol The loss of 12 moles of water by heating potash alum codechaydrate can be curitten as KAI (501) 12H20 -->> KAl(soda + 12 H20 "As by this equation 12 mole of K(Al(SO4), 12 H₂O male of KAI(50/2 moles of H20 (a) Here in the question is heated 25.8 g of k Al(soy) - 12 HD Commenting it into molas by using equalim No. of makes = mass in gm Gryam Mottater mass . - 25.8 474.3884 = 0.0544 moles So 0.0544 moles on hearing also gives 0.0544 mais (Ke Al (504) 2:124) of kal (soda 80, 0.0544f males KAl(Soyle means __Mass in gram = No. of males * Gram molecular Mass

= 0.0544 x 258.2050

= 14. 0463529 of KAl(S04), 4. (6) Converting the . no. of möles. given 45g of water to ie No. of moles = Mass in gm Giram melecular mass 45 - 2,5 moles.

KAl(SO4)-12 H2O => k Al(sobe + 12 H2O 'As by this equation

Imde 12 mole (120) I mole m - by 12 I mote I mole (HO) to get 2.5 mole to multiply by 2.5 Q.5x I mole 2.5xLmole & 2.5 mole H2O 2

So inorder to get 2.5 moles of water. 25 mae males of KAl(S04)2.12tho would 12 be required or = Converting this to gram by can Mass in grañs No. of moles x Gram Molecular Da Mais 2.5 x 474.3884 12 98.83.09 g of KA (501) 5.855 +.09