Question

Experiment 6 PRE-LABORATORY PROBLEMS NAME 1. Write a purpose statement and a summary of the procedure to include special technique equipment, chemicals, and chemical reactions to be performed, an understanding of any calculations that are important to understanding the procedure. 2. Calculate the molar mass of copper (II) Sulfate pentahydrate, Cuso,5H.O. 3. Calculate the mass percent of water present in Copper(II) sulfate pentahydrate. 4. Define the term hydrate and anhydrous. S. A 2.000 gram sample of hydrated barium carbonate was heated to dryness and the remaining compound weighed 1.570 . What is the mass percent of water in the hydrated sample? What is the molecular formula of the hydrated barium carbonate (ie How many water molecules are hydrating the barium carbonate?) 6. When the Copper (II) sulfate pentahydrate dissolves in water, what happens to the water that is part of the solid hydrated salt. 7. Copper (II)oxide can be heated until it decomposes into elemental copper and oxygen gas. How many grams of elemental Cu could be produced in the decomposition of 0.695 grams of Copper (11) oxide? 8. In the problem above, the 0.695 of CuO was formed in the reaction of 2.0038g of a Copper (ID) compound after it was reacted with NaOH and heated. What is the mass of Copper in the unknown Copper (II)oxide? SSSSSSS 9. What is the percent mass of Copper in each of the following compounds? a. CuSO,5H.0 b. CuBr, c. Cuci, 2H,0 d. Cu(NO), 3H,0 e. Cu(C,H,0.), H,0 10. Which one of the above is the unknown Copper (II) compound from problem 8? PERCENT COMPOSITION

Answer 1

btained silver ups were to remove sodium ethoxe lion from the r ollecte to procedure is not given as to when experiment is performed. 2. Cuso, .5H₂O hi 63. 5 glamol S: 32 0: 16 40:18 8. Molas mass: 63.5+ 32 + 16(4) +5 (18) = 249.5g/mol 3. Mass% of to incuson 5th = 90x100 249.5 4. Hydrate means a compound is associated with the water of crystallisation like cuso. 5 Ho whereas anhydrous means watch of crystallication will not be present of it is just cuson. 5. mass % of th20 = 100 1.540 x 100 = 100-78.5 = 21.5% - 36.072% oo Baloz.xH0 d 0.39 of water is present which corresponds to 0.3 0.055 moles of water as hydrating the BaCO3. 18

6. Cuso. .5H₂O dissolves in water then the evates in the hydrated salt becomes free water molecules, 7.26u0 2 Cut O₂ 0. 695g since, a moles of and gives a moles of cu. 0.695g of mo gives 0.695g of elemental carbon. 8. Cu ta NaOH → CuOH) o cuo of mass of copper - 0.46213 x 100 = 66.5% 0.6454 0 Коо хаа 95.5g of cuo has 63.5g of cu. 0. x= 63.5x0.695 95.5 = 0.462129 9. a) Cuso. SHO MW=249.5 249.5 9. a) wisowe i % of w= 63.5 x 100-25.45% 6) Cu Bo63.5#80x2). 223.5 63,5 x 100 = 28.411% 41.5 223.5 C) Cuct. 2H 0 : 63.5+2(35.5)+36=170.5. 63 170.5" 3.3 x 100 - 37.243% . d) eu (NO2).340, 63.5+(14+48)2 +0x18) = 24 e) cu (C₂H₂O2)₂ H0 =199.5 31.82% 28% e) is unknown 12 = 199.5