29. Solving a chemistry problem

18. When studying the kinetics of thermal decomposition of substance A, the initial concentration of which is 90 mol / m3, the values of the reaction rate constants at different temperatures were obtained
T, K 830 840 850 865 870
k, min-1 0.0067 0.01 0.0149 0.0255 0.0308
Determine: 1) by a graphical method the value of the activation energy;
2) calculate the value of the pre-exponential factor;
3) calculate the concentration of the initial substance after 15 minutes from the start of the reaction proceeding at a temperature of 840 K.