What is the energy of a wave with a frequency of 8.0x1014 Hz. Round your answer to 2 sig figs. E = hf (h = 6.63 x 10^-34)
A. 5.3x10-19 J
B. 5.30x1019 J
C. 3.75x107J
D. 2.49x1040 J
I need help with this, someone

Ineed to find the answer of this question because i dont understand it

12. calculate the hydroxide ion concentration of a solution with ph = 3.25. show all calculations leading to an answer

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