(Solved): (h) (i) Crystal formation is an important component of gravimetric analysis. What chemical process ...

(h) (i) Crystal formation is an important component of gravimetric analysis. What chemical process (not experimental condition) causes the formation of colloidal solutions instead of crystals? Name an experimental parameter that can increase the formation of crystals. Describe a process where an impurity can be incorporated into a crystal. (3 x 1 mark) i. ii. iii. The aluminum (FW 26.98 g/mole) in a 1.200 g sample of impure ammonium aluminum sulphate was precipitated with aqueous ammonia as the hydrous Al,0? xH?O. The precipitate was filtered and ignited at 1000 °C to give anhydrous Al?O3 (FW 101.96 g/mole) with a mass of 0.1798 g. Calculate the percentage of aluminum in the sample. (3 marks)