BEING TIMED. PLS HELP. WILL MARK Calculate the energy related to the following wavelength. 4.90 x 10^-7 m

2.61 x 10^18 J
3.00 x 10^8 J
4.06 x 10^-19

Why do scientists look for patterns in the world? a. patterns can explain observations. b. patterns never change, no matter what. c. patterns are easy for scientists to detect. d. patterns are all the same, through all time.

Asample of tin (ii) chloride has a mass of 0.49 g. after heating, it has a mass of 0.41 g.  what is the percent by mass of water in the hydrate?   %

If a solution contains 3 moles/liter of sodium chloride (nacl, made of sodium ions and chloride ions), what is the osmolarity of this solution