Estimate the value of the equilibrium constant at 525 K for each reaction in Problem 73.

Name: Problem 77, Chapter 18: Chemistry: Structure and Properties
Uploaded: 2021-04-28T04:17:42-08:00
Duration: 13 min 26 s
Channel: Ronald Prasad
Description: Estimate the value of the equilibrium constant at 525 K for each reaction in Problem 73.

Estimate the value of the equilibrium constant at 525 K for...

Key Concepts

van't Hoff Equation

The van't Hoff equation provides a mathematical relationship that describes how the equilibrium constant changes with temperature. By relating the change in the natural logarithm of the equilibrium constant to the inverse of the temperature, it allows one to estimate the equilibrium constant at different temperatures, provided the enthalpy change of the reaction is known.

Equilibrium Constant

The equilibrium constant (K) quantifies the ratio of the concentrations (or pressures) of products to reactants when a chemical reaction has reached equilibrium. It indicates the extent of the reaction, with a large value favoring products and a small value favoring reactants, and it is determined solely by the reaction conditions and temperature.

Temperature Dependence of Equilibrium

The value of the equilibrium constant is highly sensitive to temperature changes. An increase or decrease in temperature can shift the balance between products and reactants based on the reaction's enthalpy change, making it essential to understand and predict the effect of temperature variations on the position of equilibrium.

Transcript

00:05 So to meet the value of the equilibrium constant for each of the following reactions, in order to do so, we'll have to use the expression, long k, k as their equilibrium constant, is equal to delta h knot, minus delta h knot reaction, for r, 1 over t, plus delta s knot reaction over r for a, the equilibrium reaction is 2 co gas, plus o2 gas, will produce 2 co2 gas.

00:47 We'll have to find the delta h -0 reaction and delta s -not reaction before calculating the equilibrium constant.

00:55 Delta h -not reaction is equal to the sum, the delta -h -not formation of the products, minus the sum of the reactants, and this is equal to 2 -dh -0 formation co2 gas on the product side, minus 2 -delpa -h -namation co, delta -h -not, is equal to 2 times minus 393 .5 kilo kilojoules per mole minus two times minus 110 .5 kilojoules and this would give us value here equal to negative 56 kilojoules per mole which is equivalent to negative 56 ,000 joules per mole.

02:42 Now let's calculate delta s not and delta s not here is equal to reaction the sum the delta s not formation of the products minus the sum delta s not formation of the reactants.

03:29 This is equal to 2 times the delta s not formation of co2 gas minus 2 times the delta s not formation of co gas plus the delta s not formation of o2 gas.

04:04 This is equal to 2 times times the ltheos knot formation is 2 .13 .8 joules per mole minus 2 times 197 .7 plus 205 .2 joules per mole.

04:33 This is equal to 427 .6 joules per mole minus 402 .9 .9.

05:04 Jules per mole with delta s not reaction works out to be 24 .7 joules per mole.

05:21 Now we'll plug this in and solve for our equilibrium constant.

05:27 Lon k is equal to minus delta h not reaction over r plus delta s not.

05:44 Reaction over r so lon of k is equal to minus and then delta h knot we solved was minus 560 ,000 joules per mole over uh joules per mole sorry this is the joules per mole this is and jewels per mole kelvin.

06:25 Add that into each one of these here in the denominator.

06:32 R is 8 .314 joules per mole kelvin and plus 24 .7 joules per mole kelvin over 8 .3.

07:00 We'll find that lon k here is equal to, this is 128.

07:18 Point 3 plus 2 .97 for long k is equal to 131 .3 3 131 .27 and taking the inverse here we find that k equilibrium constant is equal to 1 .1.

07:56 0 .02 is 10 to the 57 for part a...

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