Aphoton has 4.75x10^-19 j energy. what is the frequency of this photon?

10. according to the law of conservation of mass, how does the mass of the products in a chemical reaction compare to the mass of the reactants?

The molality of calcium chloride (cacl2) in an aqueous solution is 2.46 m. what is mole fraction of the solute?

How many protons, electrons, and neutrons are in each of the following isotopes? a. zirconium-90 b. palladium-108 c. bromine-81 d. antimony-123