Which of the following would NOT be considered valid sources of error in a laboratory experiment? I: Calculation errors II: Inability to calibrate measuring devices III: Using the wrong solution for a reaction

Compounds a and b react to form compounds c and d according to the equation: aa + bb → cc + dd. under which conditions will the rate law be given by the equation: rate = k[a]a[b]b? a. the reaction takes place in one step. b. the reaction is endothermic. c. the reaction is exothermic. d. the reaction involves more than one step.