For a certain chemical reaction, the standard Gibbs free energy of reaction at 30.0 °C is 110. kJ. Calculate the equlilibriunm constant K for this reaction. Round your answer to 2 significant digits.

Explanation:

The equation that relates standard Gibbs free energy, ΔG, with equilibrium constant, K, is:

ΔG = -RT ln K

Where R is gas constant, 8.314J/molK, and T is absolute temperatue (30.0°C + 273.15 = 303.15K).

Replacing (110kJ = 110000J):

110000J/mol = -8.314J/molK*303.15K ln K

-43.644 = lnK

1.11x10⁻¹⁹ = K

when 25.0 ml of 0.700 mol/l naoh was mixed in a calorimeter with 25.0 ml of 0.700 mol/l hcl, both initially at 20.0 °c, the temperature increased to 22.1 °c. the heat capacity of the calorimeter is 279 j/°c.

the equation for the reaction is:

naoh + hcl → nacl + h₂o

moles of hcl = 0.0250 l hcl ×

0.700

mol hcl

1 l hcl = 0.0175 mol hcl

volume of solution = (25.0 + 25.0) ml = 50.0 ml

mass of solution = 50.0 ml soln ×

1.00

ml soln

= 50.0 g soln

δt=t2-t1

= (22.1 – 20.0) °c = 2.1 °c

the heats involved are

heat from neutralization + heat to warm solution + heat to warm calorimeter = 0

q1+q2+q3=0

nδh+mcδt+cδt=0

0.0175 mol ×

δh

+ 50.0 g × 4.184 j·g⁻¹°c⁻¹ × 2.1 °c + 279 j°c⁻¹ × 2.1 °c = 0

0.0175 mol ×

δh

+ 439.32 j + 585.9 j = 0

0.0175 mol ×

δh

= -1025.22 j

δh=1025.22j0.0175 mol= -58 600 j/mol = -58.6 kj/mol