Why are subscripts important in chemical formulas

In 2002, the rare earth elements mine in mountain pass, california was closed because

If you used the method of initial rates to obtain the order for no2, predict what reaction rates you would measure in the beginning of the reaction for initial concentrations of 0.200 m, 0.100 m, & 0.050 m no2.

Which statement is actually true about the relationship between activation energy and reaction rates? low activation energy barriers result in low rates. high activation energy barriers result in low rates. low activation energy barriers result in no reaction. high activation energy barriers result in no reaction.