A particular reaction has ΔG = –350 kJ and ΔS = –350 J/K at 24 °C. How much heat will be released/absorbed?

• A. –1.04×10⁵ kJ
• B. –454 kJ
• C. –8.75×10³ kJ
• D. 246 kJ
• E. +454 kJ
• F. –246 kJ

Answer: (B)

Verified step by step guidance

1. First, convert the temperature from Celsius to Kelvin. The formula is: T(K) = T(°C) + 273.15. So, 24°C becomes 297.15 K.
2. Next, convert the entropy change (ΔS) from J/K to kJ/K to match the units of ΔG. Since 1 kJ = 1000 J, divide ΔS by 1000: ΔS = -350 J/K ÷ 1000 = -0.35 kJ/K.
3. Use the Gibbs free energy equation: ΔG = ΔH - TΔS, where ΔG is the change in Gibbs free energy, ΔH is the change in enthalpy (heat released or absorbed), and T is the temperature in Kelvin.
4. Rearrange the equation to solve for ΔH: ΔH = ΔG + TΔS.
5. Substitute the known values into the equation: ΔH = -350 kJ + (297.15 K)(-0.35 kJ/K). Calculate the result to find the amount of heat released or absorbed.