An element has three naturally occurring isotopes. the relative abundances of the isotopes are 0.27%, 9.25%, and 90.48%. the most abundant isotope has an atomic mass of 19.99 amu. the least abundant isotope has an atomic mass of 20.99 amu, and the remaining isotope has an atomic mass of 21.99 amu. based on these data, what is the average atomic mass of this element? (round your answer to the nearest hundredth and do not enter units in your answer.)

Agas has a volume of 0.7 l at 300 mmhg. what would be the new volume at 900 mmhg

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

Molecular iodine, i2(g), dissociates into iodine atoms at 625 k with a first-order rate constant of 0.271 s−1. part a part complete what is the half-life for this reaction?