A metal surface is known to have a work function of 7.75 eV. If an electron was emitted from the surface of the metal at a speed of 5.45X106 m/s, what was the wavelength, in nm, of the photon used?

At a certain temperature the rate of this reaction is first order in hi with a rate constant of : 0.0632s2hig=h2g+i2g suppose a vessel contains hi at a concentration of 1.28m . calculate how long it takes for the concentration of hi to decrease to 17.0% of its initial value. you may assume no other reaction is important. round your answer to 2 significant digits.