How many of the following reactions are endothermic? Tio (s) Ti(s) + O2(g) AH = +939.7 kJ H2(g) + Cl2(g) 2 HCl(g) AH = +184.6 kJ TiO,(s) + 4 HCl(g) Tici,1) + 2 H2(g) + O2(g) AH = -233.7 kJ Tic (1) Ti(s) + 2 Cl.(g) AH = +804.2 kJ