Chromium-51 is a radioactive isotope used to label red blood cells to identify if they remain intact in the body. it has a half-life of 27.7 days. if 0.25 mg is an approximate dose amount, how much remains after 83.1 days?

Butadiene undergoes a reaction at a certain temperature in the gas phase as follows: 2c4h6(g) --> c8h12(g) the following data were collected for this reaction: time (min) [c4h6] (m) 0 0.36 15 0.30 30 0.25 48 0.19 75 0. determine the order of the reaction and the rate constant. 1st order and k = 4.3x10 -4 s-1 1st order and k = 2.3x10-4 s-1 2nd order and k = 4.3x10-4 s-1 2nd order and k = 2.3x10-4 s-1 zero and k = 4.3x10-4 s-1

Particles vibrate in a rigid structure and do not move relative to their neighbors.

Determine the empirical formula for succinic acid that is composed of 40.60% carbon, 5.18% hydrogen, and 54.22% oxygen.