Consider the following reaction, for which ∆H° = +87.9 kJ/mol and ∆S° = +170.2 J/mol·K. PCl5(g) → PCl3(g) + Cl2(g) Assume ∆H° and ∆S° do not vary appreciably with change in temperature. At what temperature will the reaction be at equilibrium when the partial pressures of each component of the reaction are under standard conditions (1.00 atm each).?

516.45K or 243.45°C

Explanation:

From

∆S= ∆H/T

∆S= change in entropy

∆H= change in enthalpy

T= temperature in Kelvin

T= ∆H/∆S

T= 87.9 ×10^3Jmol-1 / 170.2Jmol-1K-1

T= 516.45K or 243.45°C

2fe + 3h2so4 -> fe2(so4)3 + 3h2

it is necessary to balance equations in order to get the proper amount of reactants as well as products in order not to make a miscalculation.

you cannot change the subscripts as that would change the substance itself. for instance, diatomic elements such as h2 only have the subscript two when a gas. another example would be so4, if you were to change the subscript, the element would no longer be sulfate.

we change the coefficients instead as that only changes the number of molecules rather than the substance itself.

hope this !