Question

При образовании алмаза из графита энтропия углерода уменьшилась на 1,4 Дж/К. Сколько граммов алмаза получено? Энтропии алмаза и графита равны 2,38 и 5,74 Дж/(моль·К), соответственно.

Answer 1

Дано:   ΔS = 1,4 Дж/К
Sал. = 2,38 Дж/(моль*К)
Sгр. = 5,74 Дж/(моль*К)
Найти: mал.
Решение: 
     Изменение энтропии  в расчете на  1 моль: 
ΔS = Sгр. - Sал. = 5, 74 - 2,38 = 3,36 Дж/(моль*К)
     Составим и решим пропорцию:
3,36 ----- 1 моль
1,4 ------- nал. моль
nал. = 1,4/3,36 = 5/12 (моля)
mал. = nал. * Mал = 5/12 *12 =  5 (г)
(Мал.= М(С) = 12 г/моль)
Ответ: 5г

Answer 2

Calculating the Mass of Diamond Formed from Graphite

When a diamond is formed from graphite, the change in entropy of carbon can be used to calculate the mass of the diamond produced. The change in entropy (ΔS) is given as 1.4 J/K. The entropies of diamond and graphite are 2.38 J/(mol·K) and 5.74 J/(mol·K) respectively.

The change in entropy (ΔS) can be related to the change in Gibbs free energy (ΔG) using the equation:

ΔG = ΔH - TΔS

Where: - ΔG is the change in Gibbs free energy - ΔH is the change in enthalpy - T is the temperature in Kelvin - ΔS is the change in entropy

The change in Gibbs free energy can then be related to the equilibrium constant (K) for the transformation of graphite to diamond using the equation:

ΔG = -RT ln(K)

Where: - R is the gas constant (8.314 J/(mol·K)) - T is the temperature in Kelvin - K is the equilibrium constant

By equating the two expressions for ΔG, we can solve for K and then use it to find the mass of diamond formed.

Calculations

First, we can solve for the equilibrium constant (K) using the given change in entropy (ΔS) and the entropies of diamond and graphite:

ΔG = -RT ln(K) ΔG = ΔH - TΔS

By equating the two expressions for ΔG: -RT ln(K) = ΔH - TΔS

Solving for K: K = e^(-ΔH/(RT)) * e^(ΔS/R)

Now, we can use the equilibrium constant (K) to find the mass of diamond formed.

Result

Using the equilibrium constant (K) and the entropies of diamond and graphite, the mass of diamond formed can be calculated.