Chapter 21, Problem 1ASA

The efficiency of a particular catalyst is highly dependent on its zirconium content. The starting material for this preparation is received in batches that assay between 68% and 84% ZrCl4. Routine analysis based on precipitation of AgCl is feasible, it having been established that there are no sources of chloride ion other than the ZrCl4 in the sample. What sample mass should be taken to ensure an AgCl precipitate that weighs at least 0.372 g? Mass of the sample =______ g If this sample mass is used, what is the maximum mass of AgCl that can be expected in this analysis? Mass of AgCl  = _______  g To simplify calculations, what sample mass should be taken to have the percentage of ZrCl4 exceed the mass of AgCl produced by a factor of 100? Mass of the sample =  _______ g

2.3. A mixture of Na and K (m(K+Na) = 6.2 g) was dissolved in excess of water. In this reaction 2.24 L of gas were formed. Find mass fraction (in %) of K and Na in the mixture

1. The decomposition of aqueous sucrose to form the isomers glucose and fructose is a common organic reaction, which requires a strong catalyst: C12H22O11(aq) + H2O(l) → 2C6H12O6(aq).  The following data were collected during the process: Time (min) [C12H22O11] (mol/L) 0 0.316 39 0.274 80 0.238 140 0.190 210 0.146 (a)If we performed a new trial with an initial concentration of sucrose of 0.400 mol/L, what concentration would remain after 4.0 h has passed?   2. Methyl isomerizes to acetonitrile, CH3NC(g) → CH3CN(g) at 215°C.  The following data were collected during the process: Time (sec) [CH3NC] (mol/L) 2000 0.0110 5000 0.0059 8000 0.0031 12000 0.0014 15000 0.0007 2. (a)Assuming the process continues, what concentration of methyl isonitrile would we expect after 5.00 h?