At a certain temperature the rate of this reaction is first order in SO₃ with a rate constant of 0.208 s⁻¹:
2SO₃(g) → 2SO₂(g) + O₂(g)

Suppose a vessel contains SO₃ at a concentration of 1.36M.
Calculate the concentration of SO₃ in the vessel 7.30 seconds later. You may assume no other reaction is important. Round your answer to 2 significant digits.

You are attempting to recrystallize a crude product mixture. you add the appropriate amount of hot solvent and are allowing the solution to slowly cool to room temperature. however, at room temperature no crystals have appeared, which of the following methods should be used to induce crystallization? choose all correct answers. a) place the flask in an ice bath. b) swirl the contents of the flask. c) add a small seed crystal of the desired product. d) scratch the inside of the glassware using a stir rod. it can be multiple choices