University:
Boston University
Course:
GRS CH 633 | Physical Methods for Inorganic and Bioinorganic Chemistry
Academic year:

2023
Views:

448

Pages:

2
Author:

5CelestialChronicle

Take Home Discussion Quiz #5 1. (3 points) If 501 grams of Cu(OH2)62+ reacts with 108 grams of ammonia, two products are formed. One product is water and the other is unknown. How many grams of the unknown compound will be formed? Assume 100% yield. Hint: You do not need to know the formula for the unknown compound. Cu(OH2)62+ (aq) +  Unknown (aq) + 5 H2O (l) 5 NH3 (aq) (LR) Initialy: 501g or 2.92 mol 108g or 6.34mol Used/ Formed -217.6g or -1.27mo -108g or -6.34mol End 283.4g 0g/0mol ? 0 +114.2g or 6.34mol 0g 114.2g Amount of unknown=(501+108) -289-114=211.4g or 211g or 212g Amount of Unknown = 211g or 212g g 2. (3 points) 80. grams of iron(III) oxide and 54 grams of aluminum react to form an elemental iron and aluminum oxide. In the lab you only manage to get 75% yield. Initially: Fe2O3(s) + 2Al (s) 80.g or 0.50mol 54g or 2mol Change (100%yeld): -0.5mol or -80g -1mol or -27grams Change (75%yeld): -27g∙0.75=-20.25g -80g∙0.75= -60g End: 20g  33.75g a. How many in grams of the non-limiting reagent remains? 34g b. How many in grams of the limiting reagent remains? 20. g c. How many in grams of an elemental iron is formed? 42g 1 2Fe(s) 0 + +1mol or 56g 56g∙0.75=42g 42g Al2O3(s) 0 +0.5mol or 51g 51g∙0.75=38g 38g Work must be present to receive any credit. All work has to be done individually. 3. (2points) For each molecule write the molecular shape in the box below: Trigonal planer tetrahedral Trigonal planer Bent 4. (2 points) Consider the combustion reaction for butane: C4H10 (l) + O2 (g)  CO2 (g) + H2O (g) If only 132 grams of CO2 was formed and it has a 75% yield what was initial amounts of the reagents in grams? 132  100  176 g of CO2 75 1molCO2 13molO2 32 g =208g 176 gCO2    44 gCO2 8molCO2 1molO2 132g is a 75% at 100% yield: 176 gCO2  1molCO2 2molC4 H10 58 g   =58g 44 gCO2 8molCO2 1molC4 H10 Amount of C4H10(l) = 58g Amount of O2(g) = 208=210 g 2