# Problem: Consider these reactions, where M represents a generic metal.1.  2M (s) + 6HCl (aq)  →  2MCl3 (aq) + 3H2 (g)                 ΔH1 = -579.0 kJ2. HCl (g) → HCl (aq)                                                         ΔH2 = -74.8 kJ3. H2 (g) + Cl2 (g) → 2HCl (g)                                            ΔH3 = -1845.0 kJ4. MCl3 (s) → MCl3 (aq)                                                     ΔH4 = -141.0 kJUse the following information above to determine the enthalpy (kJ) of the following reaction.2 M(s) +  3Cl2 (g) → 2 MCl3 (s)

91% (59 ratings)
###### FREE Expert Solution

We’re being asked to determine the enthalpy change (ΔHrxn) for the chemical reaction:

2 M(s) + 3 Cl2(g)  2 MCl3(s)

We can use Hess’s Law to determine the enthalpy change of the overall reaction from the given reactions:

1. 2 M(s) + 6 HCl(aq)  2 MCl3(aq) + 3 H2(g)                 ΔH1 = –579.0 kJ

2. HCl(g)  HCl(aq)                                                         ΔH2 = –74.8 kJ

3. H2(g) + Cl2(g)  2 HCl(g)                                             ΔH3 = –1845.0 kJ

4. MCl3(s)  MCl3(aq)                                                      ΔH4 = –141.0 kJ

We now need to find a combination of reactions that when added up, gives us the overall reaction.

91% (59 ratings)
###### Problem Details

Consider these reactions, where M represents a generic metal.

1.  2M (s) + 6HCl (aq)  →  2MCl3 (aq) + 3H2 (g)                 ΔH1 = -579.0 kJ
2. HCl (g) → HCl (aq)                                                         ΔH2 = -74.8 kJ
3. H2 (g) + Cl2 (g) → 2HCl (g)                                            ΔH3 = -1845.0 kJ
4. MCl3 (s) → MCl3 (aq)                                                     ΔH4 = -141.0 kJ

Use the following information above to determine the enthalpy (kJ) of the following reaction.

2 M(s) +  3Cl2 (g) → 2 MCl(s)

What scientific concept do you need to know in order to solve this problem?

Our tutors have indicated that to solve this problem you will need to apply the Hess's Law concept. You can view video lessons to learn Hess's Law Or if you need more Hess's Law practice, you can also practice Hess's Law practice problems .

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Based on our data, we think this problem is relevant for Professor Woodward's class at OSU.