Chemistry, 16.11.2019 00:31 samueltaye

In which one of the following processes is δh = δe? a. 2hi(g) => h2(g) + i2(g) at atmospheric pressure. b. two moles of ammonia gas are cooled from 325 ? °c to 300 °c at 1.2 atm. c. h2o(l) => h2o(g) at 100 °c at atmospheric pressure. d. caco3(s) => cao(s) + co2(g) at 800 °c at atmospheric pressure. e. co2(s) => co2(g) at atmospheric pressure.

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Answer from: yasmineeee96371

Answer : Only option A shows $\Delta H=\Delta E$

Explanation :

Formula used :

$\Delta H=\Delta E+\Delta n_gRT$

$\Delta H$ = change in enthalpy

$\Delta E$ = change in internal energy

$\Delta n_g$ = change in moles

R = gas constant = 8.314 J/mol.K

T = temperature

According to the question, $\Delta H=\Delta E$ when the value of $\Delta n_gRT$ will be zero.

Now we have to determine the value of $\Delta n_gRT$ for the following cases.

(A) $2HI(g)\rightarrow H_2(g)+I_2(g)$ at atmospheric pressure.

In this case:

$\Delta n_g$ = change in moles

Change in moles = Number of moles of product side - Number of moles of reactant side

According to the reaction:

Change in moles = (1+1) - 2 = 2 - 2 = 0 mole

That means, value of $\Delta n_gRT$ = 0

So, in this process $\Delta H=\Delta E$

(B) Two moles of ammonia gas are cooled from 325 °C to 300 °C at 1.2 atm.

In this case:

$\Delta n_g$ = change in moles = 2

That means, value of $\Delta n_gRT$ ≠ 0

So, in this process $\Delta H\neq \Delta E$

In this case:

Change in moles = Number of moles of product side - Number of moles of reactant side

According to the reaction:

Change in moles = 1 - 0 = 1 mole

$\Delta n_g$ = change in moles = 1

That means, value of $\Delta n_gRT$ ≠ 0

So, in this process $\Delta H\neq \Delta E$

(D) $CaCO_3(s)\rightarrow CaO(s)+CO_2(g)$ at 800 °C at atmospheric pressure.

In this case:

Change in moles = Number of moles of product side - Number of moles of reactant side

According to the reaction:

Change in moles = 1 - 0 = 1 mole

$\Delta n_g$ = change in moles = 1

That means, value of $\Delta n_gRT$ ≠ 0

So, in this process $\Delta H\neq \Delta E$

(E) $CO_2(s)\rightarrow CO_2(g)$ at atmospheric pressure.

In this case:

Change in moles = Number of moles of product side - Number of moles of reactant side

According to the reaction:

Change in moles = 1 - 0 = 1 mole

$\Delta n_g$ = change in moles = 1

That means, value of $\Delta n_gRT$ ≠ 0

So, in this process $\Delta H\neq \Delta E$

Hence, from this we conclude that, only option A shows $\Delta H=\Delta E$

Answer from: Quest

answer: atomic mass was originally used to arrange elements on the periodic table, but is no longer used to organize the modern version.

explanation:

originally atomic mass was used to arrange elements on the periodic table from left to right in a row. each column then shows similar properties of elements of a group.

in modern periodic table, the atoms are arranged in increasing atomic number. as atomic number represents the number of protons in an atom which is unique for every atom.

Answer from: Quest

Ibelieve the answer is weathering,hope my answer has you : )

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In which one of the following processes is δh = δe? a. 2hi(g) => h2(g) + i2(g) at atmospheric p...