The average rate of disappearance of A between 20 s and 40 s i is how many mol/s? a) 8.5 x 10^-4 b) 1.7 x 10^-3 c) 590  d) 7.1 x 10^-3 e) 1.4 x 10^-3

How long would it take in minutes,  for the amount of potassium -44 to decrease from 80.0 to 10.0mg

A gas sample of Br2 and H2 is irradiated with light with a wavelength range between 440 and 500 nm. It is known that this radiation has sufficient energy to obtain HBr. With this data you can say:a) All the molecules present will give rise to HBr, because the wavelengths are appropriate to activate all the reactants.b) The rate of HBr formation depends directly on the concentration of H2 in the sample.c) The rate of HBr formation depends directly on the concentration of Br2 in the sample.d) If the sample is irradiated with a wavelength of 580 nm, there is no guarantee that HBr will be obtained.

It is the lab of Decomposition of Hydrogen Peroxide.In this experiment, you will initially determine the initial reaction rate in units of kPa/s. Show how you would convert the initial reaction rate to mol/L - s

Pls help ASAP

Fallout from nuclear weapons tests in the atmosphere is mainly 90Sr and 137Cs , which have 28.6- and 32.2-y half-lives, respectively. Atmospheric tests were terminated in most countries in 1963, although China only did so in 1980. It has been found that environmental activities of these two isotopes are decreasing faster than their half-lives. Why might this be?

Radioactive materials are often used in biological studies. A radiation biologist studies the rate of decomposition of a certain substance and obtains the following data: Time (days) 0 4.0 8.0 12.0 16.0 Mass (μg) 26.20 18.13 12.55 8.69 6.01 How many micrograms will remain after 26 days?