Which of these statements are true? Select all that apply. The Delta. Hrxn for the reaction C(s) O2(g) Right arrow. CO2(g) is the same as the Delta. Hf for CO2(g). The Delta. Hrxn for the reaction Na(s) Cl2(g) Right arrow. 2NaCl(s) is the same as the Delta. Hf for NaCl(s). The Delta. Hf for Br2(l) is 0 kJ/mol by definition. To determine the Delta. Hf for H2O(g), just reverse the sign of the Delta. Hrxn for the reaction 2H2O(l) Right arrow. 2H2(g) O2(g). The Delta. Hf for N2(l) is 0 kJ/mol by definition. The Delta. Hrxn for the reaction 1. 5H2(g) 0. 5N2(g) Right arrow. NH3(g) is the same as the Delta. Hf for NH3(g).