How many half lives will have passed if 7500 atoms of carbon-14 remain? How old would the rock be? (Pls explain, I'm very confused)

Assuming complete dissociation of the solute, how many grams of kno3 must be added to 275 ml of water to produce a solution that freezes at -14.5 c? the freezing point for pure water is 0.0 c and k_f is equal to 1.86 c/m

Which statement is true about the model of the electromagnetic spectrum a: it change the frequencies of light. b: it compare wavelengths of light. c: the color of light waves can be changed using the model. d: the intensities of light waves can be decreased using the model.

Select the correct answer. wax is a nonpolar substance. in which type of substance is it most soluble?