One of the many isotopes used in cancer treatment is , with a half-life of 2.70 d. Determine the mass of this isotope that is required to give an activity of 205 C

Salicylic acid is a very important acid. it is used to synthesize the aspirin by treating with acetic anhydride. a 0.2015-g sample of salicylic acid was dissolved in a 100.00-ml volumetric flask, and the solution was diluted to the mark. a 10-ml aliquot of this solution was titrated with standard naoh (0.01130 + 0.2% n) to a phenolphthalein faint pink color end point at 19.81 ml. (a) (calculate the normality of the salicylic acid solution used in the titration. (b) assuming the salicylic acid is pure, what is the equivalent weight of the salicylic acid? practice problems for the final exam (continued) (c) (calculate the inherent error in the determination of the equivalent weight you calculated in part (b). use the following absolute errors in the equipment /glassware when calculating the inherent error. 5.00-ml pipet: + 0.02 ml 100-ml volumetric flask: + 0.08 ml analytical balance: + 0.2 mg 25-ml buret: + 0.03 ml

1. an experiment in your science class lists the materials needed for the lab. it is your job, as a lab partner, to measure out 25 ml of distilled water and 2.5 grams of magnesium. what lab measuring tools would you choose to measure each substance and how would you use each tool to get the correct amounts? be sure to describe the process you would follow step-by-step. (5 points) 2.which of the following is an si base unit for measuring mass? (2 points) ampere gram meter pound 3.which of the following is an si base unit for time? (2 points) decades hours minutes seconds 4.which of the following tools should a scientist use to measure an object in milligrams? (2 points) graduated cylinder pan balance tape measure thermometer 4.which of the following tools should a scientist use to measure an object in milligrams? (2 points) graduated cylinder pan balance tape measure thermometer. 5.a pencil beside a metric ruler. the ruler is scaled from 1 centimeter to 10 centimeters, with markings for millimeters between each number. one end of the pencil is beside the 0 on the ruler, and the pencil point is beside the 5. which of the following measurements is accurate but not precise? (2 points) 5 mm 5 cm 50 mm 50 cm 6. which of the following prefixes represents the largest value? (2 points) giga hector kilo milli 7. which of the following types of graphs is best for plotting the percentages of a whole value in a data set? (2 points) bar graph circle graph histogram line graph

Some liquids can be distilled, but only at temperatures that are so high that it is impractical, or so high the compound decomposes. explain why distillation such compounds at significantly less than atmospheric pressure (some degree of vacuum) would solve this problem.