22. Ayesha is the technician preparing the spiked samples and performing the analysis. For the spiked sample, she calculates the concentration of in spiked sample to be 27.1 mg/L and she knows that she spiked a concentration of 20 mg/L. If the calculated % recovery is calculated to be 112%, then what was the analyte concentration in the unspiked sample

1. suppose a reaction mixture, when diluted with water, afforded 300 ml of an aqueous solution of 30 g of the reaction product malononitrile [ch2(cn)2], which is to be isolated by extraction with ether. the solubility of malononitrile in ether at room temperature is 20.0 g/100 ml, and in water is 13.3 g/100 ml. what weight of malononitrile would be recovered by extraction with (a) three 100-ml portions of ether and (b) one 300-ml portion of ether? suggestion: for each extraction, let x equal the weight extracted into the ether layer. in part (a), the concentration in the ether layer is x/100 and in the water layer is (30 x)/300; the ratio of these quantities is equal to k 20/13.3.

The best solution for preventing harm to people and pets from severe hurricanes involves determining and warning residents about what

Which common material is an example of a polymer? (25 pts) a. steel b. plastic c. petroleum d. rubbing alcohol