Answers: 3
Chemistry, 21.06.2019 17:10
Abullet found at a crime scene may be used as evidence in a trial if the percentage of metals match to the composition of metals in a bullet from the suspect's ammunition. a forensic scientist's analysis of the bullet shows that it contains 11.9 g of lead, 0.5 g of tin, and 0.8 b of antimony. what is the percentage of lead metal in the bullet? express your answers to the one's place.
Answers: 2
Chemistry, 22.06.2019 00:00
Which of the following statements is true? a. elements in the last period are radioactive. b. atomic weight is the same as atomic mass. c. elements in the same group have the same number of electron shells. d. atomic number equals the number of neutrons in the nucleus of an atom.
Answers: 1
Chemistry, 22.06.2019 05:30
A3.37-mg sample of protein was chemically digested to convert its nitrogen into ammonia and then diluted to 100.0 ml. then 10.0 ml of this solution was placed in a 50-ml volumetric flask and treated with 5 ml of phenol solution plus 2 ml of sodium hypochlorite solution. the sample was diluted to 50.0 ml, and the absorbance at 625 nm was measured in a 1.00-cm cuvette and found to be 0.486. for reference, a standard solution was prepared from 10.0 mg of nh4cl (molar mass = 53.49 grams/mole) dissolved in 1.00 l of water. then 10.0 ml of this standard was placed in a 50-ml volumetric flask, treated in the same manner as the unknown, and the absorbance found to be 0.323. finally, a reagent blank was prepared using distilled water in place of unknown, it was treated in the same manner as the unknown, and the absorbance found to be 0.076. calculate the weight percent of nitrogen in the protein.
Answers: 1
Identify the phase change described by the following equations.
a. C18H38(s) → C18H38(l)
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