By keeping food cold, the growth of microorganisms is minimized. stopped and they are killed. increased. not changed. . Determination of Mass Percent of Ammonium Chloride Fill in the following on your report sheet: Mass of evaporating dish and original sample: 54.85 g Mass of evaporating dish: 52.31 g Mass of original sample: 2.54g Mass of evaporating dish (and sample) after subliming NH4Cl: 54.73 g Mass of NH4Cl: 0.12g Percent of NH4Cl: 4.72% B. Determination of Mass Percent of Sodium Chloride Fill in the following on your report sheet: Mass of evaporating dish, watch glass, and NaCl: 64.36 g Mass of evaporating dish and watch glass: 63.83 g Mass of NaCl: 0.53g Percent of NaCl (show calculations): 20.87g C. Determination of Mass Percent of Silicon Dioxide Fill in the following on your report sheet: Mass of evaporating dish and SiO2: 54.26 g Mass of evaporating dish: 52.31 g Mass of SiO2: 1.95g Percent of SiO2 (show calculations): (determine on your own, see the equation in Example 2.1) D. Determination of Percent Recovery All of Part D. on the report sheet: (determine on your own) *************************************************************************************** D. Determination of Percent Recovery Mass of original sample 2.54g Mass of determined (NH4Cl + NaCl + SiO2) 2.60g Differences in these welghts 0.06g Percent recovery of matter = g matter recovered /g original sample x 100% = 102,4% Account for your errors