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BigorU [14]
3 years ago
13

Acetylene, c2h2, has a standard enthalpy of formation, δh° = 226.7 kj/mol, and a standard entropy change for its formation from

its elements, δs° = 58.8 j/k•mol. the standard free energy of formation of acetylene is ________ kj/mol.
Chemistry
2 answers:
VLD [36.1K]3 years ago
5 0
ΔG⁰ = ΔH⁰ - T ΔS⁰

ΔG⁰ : Standard free energy of formation of acetylene

ΔH⁰ : Standard enthalpy of formation (226.7 kJ/mol)

ΔS⁰ : Standard entropy change (58.8 J / K. mol)

T : Temperature 25°C = 298 K (room temperature)

ΔG⁰ = 226.7 - (298 x 58.8 x 10⁻³) = 209.2 kJ /mol
natima [27]3 years ago
5 0

Explanation:

The given data is as follows.

     \Delta H^{o} = 226.7 kJ/K mol,      

     \Delta S^{o} = 58.8 J/mol = 58.8 \times 10^{-3} kJ/K mol

         T = 25^{o}C = (25 + 273) K = 298 K

Now, calculate the standard free energy of formation of acetylene (C_{2}H_{2}) as follows.

             \Delta G^{o} = \Delta H^{o} - T \Delta S^{o}

                        = 226.7 - kJ/mol - 298 K \times 58.8 \times 10^{-3} kJ/K mol[/tex]

                        = 209.2 kJ/mol

Thus, we can conclude that the standard free energy of formation of acetylene is 209.2 kJ/mol.

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2 years ago
For the following reactions, predict the products and write the balanced formula equation, complete ionic equation, and net ioni
stealth61 [152]

Answer:

.

Explanation:

To predict the products of these reactions we need to know the kind of reactions. All these reactions are double replacement reaction. In these kinds of reactions, the products will be the result of exchanging ions in the reactants. So, the first step is to identify the ions.  

For the reaction, we have Hg2(NO3)2 and CuSO4.  We have the ions Hg+1,  NO3-1,   Cu+2 and SO4-2  

The way to make this exchange is putting together positive in one species with the negative of the other species. Following that rule we have

Hg^{+1}  - - -  (SO_{4})^{-2}[/text]&#10;the oxidation number will tell you the subscript for each species in the compound. In this case, is Hg2(SO4)  [tex]Cu^{+2} - - -  (NO_{3})^{-1}  - - ->  Cu(NO_{3})_{2} [/text]  &#10;So, the products for this reaction will be&#10;  [tex]Hg_{2} (NO_{3})_{2}(aq) + CuSO_{4}(aq)  -->  Hg_{2}SO_{4} + Cu(NO_{3})_{2}[/text]&#10;&#10;After this, we proceed to balance the equation. For this, we check that we have the same number of each element on both sides of the equation. In this case, we can see that we have the same number, so the equation is balanced.  Finally, we check the rules of solubility to see if the species are soluble in water or not. In this case sulfates area always soluble except for mercury so Hg2(SO4) precipitates in the solution (pre). Nitrates are always soluble so Cu(NO3)2 is soluble (aq)  &#10;[tex] Hg_{2}(NO_{3})_{2}(aq) + CuSO_{4}(aq)  - -> Hg_{2}SO_{4} (pre) + Cu(NO_{3})_{2}(aq)

The complete ionic equation allows to show which of the reactants or products exist primarily as ions.  For this reaction this will be:

2Hg^{+1}(aq)  + 2(NO_{3})^{-1}(aq) + (SO_{4})^{-2}(aq)  + Cu^{+2}(aq)    -->  Hg_{2}SO_{4} (pre)+ Cu^{+2}(aq)    + (NO_{3})^{-1}(aq) [/text]&#10;&#10;To get net ionic equation we take away the ions that did not participate in the reactions. In other words the ones that are the same on both sides in the equation. In this case we see that [tex] Cu^{+2}(aq)   and  (NO_{3})^{-1}(aq) [/text] are the same on both sides so those ions are not include in the net ionic equation.  This is:&#10;[tex] 2Hg^{+1}(aq)  + (SO_{4})^{-2}(aq)  -->  Hg_{2}SO_{4} (pre) [/text]&#10;&#10;B [tex] Ni(NO_{3})_{2}(aq) + CaCl_{2}(aq)

ions (1) Ni^{+2}  and (NO_{3})^{-1}

ions (2) Ca^{+2} and Cl^{-1}

Exchanging  

Ni^{+2}  ---- Cl^{-1}  -->  NiCl_{2}  

Ca^{+2} ---  (NO_{3})^{-1}  -->  Ca(NO_{3})_{2}  

Products  

Ni(NO_{3})_{2}(aq) + CaCl_{2}(aq) -->  NiCl_{2}  + Ca(NO_{3})_{2}  

The equation is already balanced

Chlorides are always soluble except Ag+, TI+, Pb+2 and Hg2+2. NiCl2 is soluble (aq)

Nitrates are always soluble. Ca(NO3)2 is soluble (aq)  

Since both compounds are soluble, we can say that there is not reaction.

Complete ionic equation  

Ni^{+2}(aq) + 2(NO_{3})^{-1}  (aq) + Ca^{+2}(aq) + 2Cl^{-1}(aq) - - > Ni^{+2}(aq) + 2(NO_{3})^{-1}  (aq) + Ca^{+2}(aq) + 2Cl^{-1}(aq)

Net ionic equation:

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C K_{2}CO_{3}(aq) + MgI_{2}(aq)

Ions(1) K^{+1}  and (CO_{3})^{-2}

Ions(2) Mg^{+2}  and l^{-1}

Exchanging  

K^{+1}  ---  l^{-1}  - - >  KI

Mg^{+2}  ---  (CO_{3})^{-2}  - - >  Ca(CO_{3})

Products  

K_{2}CO_{3}(aq) + MgI_{2}(aq) - ->   Kl + MgCO_{3}  

The equation is not balanced

Balance equation is  

K_{2}CO_{3}(aq) + MgI_{2}(aq) - ->  2Kl (aq) + MgCO_{3} (pre)  

iodides are always soluble except Ag+, TI+, Pb+2 and Hg2+2. KI is soluble (aq)

carbonates are always insoluble except group 1 cations. MgCO3 is insoluble (pre)

complete ionic equation  

2K^{+1}(aq)  + (CO_{3})^{-2}(aq)  + Mg^{+2}(aq)   + 2l^{-1}(aq)  - - > MgCO_{3} (pre) + 2K^{+1}(aq)  + 2l^{-1}(aq)  

Net ionic equation

(CO_{3})^{-2}(aq)  + Mg^{+2}(aq)  - - > MgCO_{3} (pre)  

D Na_{2}CrO_{4}(aq) + AlBr_{3}(aq)  

Ions(1) Na^{+1}  and (CrO_{4})^{-2}

Ions(2) Al^{+3} and Br^{-1}

Exchanging  

Na^{+1}  ---- Br^{-1} - ->  NaBr  

Al^{+3} ---  (CrO_{4})^{-2} - ->  Al_{2}(CrO_{4})_{3}

Products  

Na_{2}CrO_{4}(aq) + AlBr_{3}(aq) - ->  NaBr  + Al_{2}(CrO_{4})_{3}

The equation is not balanced

Balance equation is  

3Na_{2}CrO_{4}(aq) + 2AlBr_{3}(aq) - -> 6NaBr  + Al_{2}(CrO_{4})_{3}

bromides are always soluble except Ag+, TI+, Pb+2 and Hg2+2. NaBr is soluble (aq)

chromates are always insoluble except group 1 cations. Al2(CrO4)3 is insoluble  (pre)

3Na_{2}CrO_{4}(aq) + 2AlBr_{3}(aq) - ->  6NaBr(aq) + Al_{2}(CrO_{4})_{3}(pre)

Complete ionic equation

6Na^{+1}(aq)  + 3(CrO_{4})^{-2}(aq) + 2Al^{+3}(aq) + 6Br^{-1}(aq) - -> Al_{2}(CrO_{4})_{3}(pre) +6Br^{-1}(aq) +  6Na^{+1}(aq)  

Net ionic equation

3(CrO_{4})^{-2}(aq) + 2Al^{+3}(aq) - -> Al_{2}(CrO_{4})_{3}(pre)  

6 0
3 years ago
A box contains identical balls of which 12 are red, 18 white and 8 blue. Three balls are drawn from the box one after the other
svet-max [94.6K]

Answer:

a) 12/323

b) 8/233

Explanation:

a) The probability of a red ball being drawn is 12/38, or in a simplified fraction, 6/19. To find the probability that 3 are red you would multiply the probability of the fraction for each, except subtracting one from the total each time as the drawn is done without replacement. This is done as follows: 6/19 × 6/18 × 6/17= 12/323

b) The probability of drawing a blue ball is 8/38, or 4/19. To find that the first one is blue and the rest are red, the equation is done as follows: 4/19 × 6/18 × 6/17 = 8/233

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Answer:

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Determine total H for bonds broken and formed, the overall change in H, and the final answer with units. Is it ENDOthermic or EX
Mrac [35]
  • E(Bonds broken) = 1371 kJ/mol reaction
  • E(Bonds formed) = 1852 kJ/mol reaction
  • ΔH = -481 kJ/mol.
  • The reaction is exothermic.
<h3>Explanation</h3>

2 H-H + O=O → 2 H-O-H

There are two moles of H-H bonds and one mole of O=O bonds in one mole of reactants. All of them will break in the reaction. That will absorb

  • E(Bonds broken) = 2 × 436 + 499 = 1371 kJ/mol reaction.
  • ΔH(Breaking bonds) = +1371 kJ/mol

Each mole of the reaction will form two moles of water molecules. Each mole of H₂O molecules have two moles O-H bonds. Two moles of the molecule will have four moles of O-H bonds. Forming all those bond will release

  • E(Bonds formed) = 2 × 2 × 463 = 1852 kJ/mol reaction.
  • ΔH(Forming bonds) = - 1852 kJ/mol

Heat of the reaction:

  • \Delta H_{\text{rxn}} = \Delta H(\text{Breaking bonds}) + \Delta H(\text{Forming bonds})\\\phantom{ \Delta H_{\text{rxn}}} = +1371 + (-1852) \\\phantom{ \Delta H_{\text{rxn}}} = -481 \; \text{kJ} / \text{mol}

\Delta H_{\text{rxn}} is negative. As a result, the reaction is exothermic.

3 0
3 years ago
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