wk 3 hw 5

[206190205]

Consider these reactions, where M represents a generic metal.
1. 2M(s) + 6 HCl(aq) --> 2MCl3(aq) + 3H2(g) H1=-811.0 kj
2. HCl(g) --> HCl(aq) H2= -74.7 kj
3. H2(g) + Cl2(g) --> 2HCl(g) H3= -1845.0 kj
4. MCl3(s) --> MCl3(aq) H4= -454.0 kj
Use the given information to determine the enthalpy of the reaction
2M(s) + 3Cl2(g) --> 2MCl3(s)
How do you know which one to choose to do the reverse direction?

[Ashely_Pavon_2E]

You know when to do the reverse reactions based on what needs to cancel out and what needs to be in the final equation. For instance you would flip the fourth reaction because you want the solid form to be in the product side for your final equation, and you want the aqueous one to cancel out.