Which transition is associated with an emission of energy? n = 5 to n = 4

n = 4 to n = 7

If 22.5 liters of oxygen reacted with excess of hydrogen, how many liters of water vapor could be produced?

In the experiment you asked to react hydrochloric acid and with sodium hydroxide. when measuring the volume of the reactants, which instrument would give the greatest precision.

The appropriate concentration for an iodine sanitizer is