What Is the Standard Molar Enthalpy Change D H Rxn

question 33

Multiple Choice

What is the standard molar enthalpy change D H rxn for the following reactions using the standard molar enthalpies of formations provided?
SiCl 4 ( ) + 2 H₂ O ( ) SiO₂ (s) + 4 HCl (g) D H rxn = ???
D H f (SiCl 4 ) = - 640.1 kJ/mol D H f (SiO₂ ) = - 910.9 kJ/mol D H f (H₂ O) = - 285.8 kJ/mol D H f (HCl) = - 92.3 kJ/mol

• A) - 2491.8 kJ/mol
• B) - 1929.1 kJ/mol
• C) - 77.3 kJ/mol
• D) - 68.4 kJ/mol
• E) None of these

---

Definitions:

Counseling Efficacy

The effectiveness or success of counseling interventions or practices.

Control Group

In experimental research, a group of participants that does not receive the treatment or intervention, serving as a baseline to compare the effects of the treatment.

Dismantling Strategy

An approach in research or therapy that involves breaking down a complex intervention into its components to understand its effectiveness.

Additive Strategy

In problem-solving, an approach where solutions are built by sequentially adding components that contribute toward a solution.