4. Write the balanced equation for CH4+Cl2„_CH2Cl2+HCl 4a. For the reaction in problem 4, ƒ´H = -118.3 kcal/mol. Identify whether this is an exothermic or endothermic reaction. Calculate the ƒ´H when 6.00 g of Cl2 are used in the reaction

Answered above.

To determine whether the reaction is exothermic or endothermic, we need to analyze the sign of the enthalpy change (∆H). If ∆H is negative, the reaction is exothermic, meaning it releases heat. If ∆H is positive, the reaction is endothermic, meaning it absorbs heat.

The balanced equation for the reaction is:
CH4 + Cl2 → CH2Cl2 + HCl

Now, let's calculate the ∆H when 6.00 g of Cl2 are used in the reaction.

To calculate the ∆H, we need to use the given ∆H value (-118.3 kcal/mol) and the stoichiometry of the reaction.

1 mole of Cl2 reacts with 1 mole of CH4, producing 1 mole of CH2Cl2 and 1 mole of HCl.

First, we need to calculate the moles of Cl2 used:

molecular weight of Cl2 = 35.45 g/mol
moles of Cl2 = mass of Cl2 / molecular weight of Cl2

moles of Cl2 = 6.00 g / 35.45 g/mol = 0.169 mol Cl2

Now, using the stoichiometry of the reaction, we can calculate the ∆H:

∆H = -118.3 kcal/mol (given)
∆H = -118.3 kcal/mol x (0.169 mol Cl2)

∆H = -19.99 kcal

Therefore, the ∆H (enthalpy change) when 6.00 g of Cl2 is used in the reaction is approximately -19.99 kcal. Since the value is negative, it indicates that the reaction is exothermic.