A substance was analysed and found to contain 26.57 % potassium, 35.36% chromium, and 38.07 % oxygen by mass.
What is the empirical formula of the substance?

Select one:
question
O a. K2Cr205
O b. K2Cr207
O c. KCr2O7
O d. K_Cro

Cobalt-60 is an artificial radioisotope that is produced in a nuclear reactor and is used as a gamma-ray source in the treatment of certain types of cancer. if the wavelength of the gamma radiation from a cobalt-60 source is 1.00 × 10-3 nm, calculate the energy of a photon of this radiation.

Arock can be broken down into different kinds of substances by physical processes. no chemical reactions are needed to separate different parts of a rock into pure substances. this is because a rock is a(n)

Newtons second law deals most cosely with