select all the correct answers. based on the enthalpy changes given for the reactions, which reactions are…

select all the correct answers. based on the enthalpy changes given for the reactions, which reactions are endothermic? 2h₂o → 2h₂ + o₂, δh = 484 kj c + o₂ → co₂, δh = -394 kj h₂ + br₂ → 2hbr, δh = -73 kj 2nh₃ → n₂ + 3h₂, δh = 92 kj

select all the correct answers. based on the enthalpy changes given for the reactions, which reactions are endothermic? 2h₂o → 2h₂ + o₂, δh = 484 kj c + o₂ → co₂, δh = -394 kj h₂ + br₂ → 2hbr, δh = -73 kj 2nh₃ → n₂ + 3h₂, δh = 92 kj

Answer

Explanation:

Step1: Recall endothermic reaction definition

An endothermic reaction has a positive $\Delta H$.

Step2: Analyze each reaction

For $2H_2O\rightarrow2H_2 + O_2,\Delta H = 484\ kJ$, $\Delta H>0$, so it is endothermic. For $C + O_2\rightarrow CO_2,\Delta H=- 394\ kJ$, $\Delta H < 0$, so it is exothermic. For $H_2+Br_2\rightarrow2HBr,\Delta H = - 73\ kJ$, $\Delta H<0$, so it is exothermic. For $2NH_3\rightarrow N_2 + 3H_2,\Delta H = 92\ kJ$, $\Delta H>0$, so it is endothermic.

Answer:

$2H_2O\rightarrow2H_2 + O_2,\Delta H = 484\ kJ$; $2NH_3\rightarrow N_2 + 3H_2,\Delta H = 92\ kJ$