Calculate the enthalpy of reaction.

D + F --> G + M
using the following equations and data:
G + C --> A + B ΔH = +277 kJ
C + F --> A ΔH = +303 kJ
D  B --> M ΔH = -158 kJ

To calculate the enthalpy of the reaction D + F --> G + M, we can use Hess's Law, which states that if a reaction can be expressed as a sum of two or more other reactions, the overall enthalpy change is the sum of the enthalpy changes of the individual reactions.

1. Given reaction: G + C --> A + B ΔH = +277 kJ

2. Given reaction: C + F --> A ΔH = +303 kJ

3. Given reaction: D --> B --> M ΔH = -158 kJ

We need to manipulate these reactions to obtain the desired reaction:

Step 1: Multiply reaction 1 by -1:
-G - C --> -A - B ΔH = -277 kJ

Step 2: Add reaction 2 and manipulated reaction 1:
(C + F) + (-G - C) --> (A + B) + (-A - B)
Simplifying, we get:
F - G --> 0 ΔH = -277 kJ + 303 kJ
F - G --> 0 ΔH = +26 kJ

Step 3: Combine the resulting equation from Step 2 with reaction 3:
(F - G) + D --> 0 + M ΔH = +26 kJ - 158 kJ
D + F - G --> M ΔH = -132 kJ

Therefore, the enthalpy of the reaction D + F --> G + M is -132 kJ.

To calculate the enthalpy of the reaction D + F -> G + M, we need to use Hess's law, which states that the total enthalpy change of a reaction is independent of the route taken.

We can break down this reaction into multiple steps using the given equations:

1. Combine the equations to match the reactants and products of the given reaction:
G + C --> A + B (Multiplied by 2)
C + F --> A (Multiplied by 1)
D  B --> M (Multiplied by 2)

2. Determine the enthalpy change for each of the steps:
Step 1: G + C --> A + B (ΔH = +277 kJ)
Step 2: C + F --> A (ΔH = +303 kJ)
Step 3: D  B --> M (ΔH = -158 kJ)

3. Multiply the equations as needed:
2 * (Step 1): 2G + 2C --> 2A + 2B (ΔH = 2 * +277 kJ)
2 * (Step 2): 2C + 2F --> 2A (ΔH = 2 * +303 kJ)
2 * (Step 3): 2D  2B --> 2M (ΔH = 2 * -158 kJ)

4. Combine the equations to match the overall reaction:
2G + 2C + 2F + 2D --> 2A + 2B + 2M

5. Add up the enthalpy changes of the individual steps to get the total enthalpy change of the reaction:
ΔH_total = ΔH_step1 + ΔH_step2 + ΔH_step3
ΔH_total = [2 * (+277 kJ)] + [2 * (+303 kJ)] + [2 * (-158 kJ)]

By substituting the given values into the equation above, you can calculate the enthalpy of the reaction.