A chemist has two lasers, Laser-A and Laser-B. It is observed that the two lasers emit visible light and that the wavelength of the light emitted by Laser-A is half as long as the wavelength of the light emitted
by Laser B. Which of the following statements could possibly be true?
(a) Laser-B will have photons that are twice as energetic as those of Laser-A.
(b) The frequency of the photons emitted by Laser-B will be twice that of the photons emitted by LaserA.
(c) Laser-A emits red light and Laser-B emits yellow light.
(d) All of these statements could possibly be true.
(e) none of these statements could possibly be true

Astudent is given a sample of a blue copper sulfate hydrate. he weighs the sample in a dry covered porcelain crucible and got a mass of 23.875 g for the crucible, lid, and sample. the mass of the empty crucible and lid was found earlier to be 22.652 g. he then heats the crucible to expel the water of hydration, keeping the crucible at red heat for 10 minutes with the lid slightly ajar. on colling, he finds the mass of crucible, lid, and contents to be 23.403 g. the sample was changed in the process to very light clue anhydrous cuso4. if there are again 100.0 g of hydrate, how many grams of cuso4 are in it? how many moles of cuso4? (hint: molar mass of cuso4 = 159.6 g / mole. what per cent of the hydrate is cuso4? you may convert the mass of cuso4 to moles.)

The characteristic of two different types of reactions are shown below. reaction a: electrons are gained by the atoms of an element. reaction b: protons are lost by the atom of and element. which statement is true about the atoms of the elements that participate in the two reactions? a: their identity changes in both reaction a and b. b: their identity changes in reaction a but not b. c: their identity changes in reaction b but not a. d: their identity remains the same.

What is the empirical formula for c4h8o2