The value of DHfe for Al2O3 (s) is __________ kJ.

Expert Solution

The ΔH_f of a substance is actually the heat of formation released or absorbed during the reaction. Generally it is calculated for the entire reaction.

Now if we consider the formation of Al2O3 (s), then the formation reaction is-

2 Al(s) + 3 O2(g) ------------------> 2 Al2O3(s)

Now ΔH_f for this reaction will be-

ΔH_f = net heat of formation of products - net heat of formation of reactants

= Σn(ΔH_f)Products − Σn(ΔH_f)Reactants

= H_f (2 Al2O3(s)) - [H_f (2 Al(s)) + H_f (3 O2(g)) ]

= 2 * H_f (Al2O3(s)) - 2* H_f (Al(s)) - 3* H_f (O2(g))

Now putting the values form a reference table-

ΔH_f = 2 * H_f (Al2O3(s)) - 2* H_f (Al(s)) - 3* H_f (O2(g))

= 2 mols * (−1675.5) - 2* 0 - 3* 0 because heat of formation of naturally available elements = 0

= - 3,351 kJ

So value of ΔH_f for Al2O3 (s) is _- 3,351 kJ

queen_honey_blossom answered 2 years ago

Al2(CO3)3 (s) è Al2O3 (s) + 3 CO2 (g) ∆H = +579 kJ a. What kind...

Al2(CO3)3 (s) è Al2O3 (s) + 3 CO2 (g) ∆H = +579 kJ a. What kind of chemical reaction is taking place? Is it endo- or exothermic? Explain how you know both answers. b. Predict the change in enthalpy for each of the following reactions: 1. 5 Al2(CO3)3 (s) è 5 Al2O3 (s) + 15 CO2 (g) ∆H = ?? 2. 3 Al2O3 (s) + 9 CO2 (g) è 3 Al2(CO3)3 (s) ∆H = ?? 3. Write...

Cr2O3(s) + 2Al(s) ---------> 2Cr(s) + Al2O3(s)

Cr2O3(s) + 2Al(s) ---------> 2Cr(s) + Al2O3(s)What loses electrons? ________ What gains electrons? ________ What is oxidized? ________ What is reduced? ________ What is the oxidizing agent? ________ What is the reducing agent? ________ Total electrons transferred per reaction cycle: ________

2 K[Al(OH)4](aq) + H2SO4(aq) ⟶ K2SO4(aq) + Al2O3(s) + 2H2O(l) K2SO4(aq) + Al2O3(s) + 3 H2SO4(aq)...

2 K[Al(OH)4](aq) + H2SO4(aq) ⟶ K2SO4(aq) + Al2O3(s) + 2H2O(l) K2SO4(aq) + Al2O3(s) + 3 H2SO4(aq) ⟶ 2 KAl(SO4)2(aq) + 3 H2O(l). What is the mole-to-mole ratio between the K[Al(OH)4](aq) and the KAl(SO4)3(aq) product in this reaction? What is the overall mole-to-mole ratio between the aluminum metal reactant and the alum product, KAl(SO4)2•12 H2O(s)

23.balance Al2O3(s)+NaOH(i)+Hf(g)--> Na3AlF6+H2O(g) a. If 11.1 kilograms of Al2O3(s), 59.4 kilograms of NaOH(l), and 59.4 kilograms...

23.balance Al2O3(s)+NaOH(i)+Hf(g)--> Na3AlF6+H2O(g) a. If 11.1 kilograms of Al2O3(s), 59.4 kilograms of NaOH(l), and 59.4 kilograms of HF(g) react completely, how b. many kilograms of cryolite will be produced? c. Which reactants will be in excess? What is the total mass of the excess reactants left over after the reaction is complete?

A composite of Al2O3 particles in an epoxy matrix contains 10 wt.% Al2O3. What are the...

A composite of Al2O3 particles in an epoxy matrix contains 10 wt.% Al2O3. What are the upper and lower bounds on the elastic modulus of the composite? Data: ρAl2O3 = 3.95 g/cm3 , EAl2O3 = 300 GPa, ρepoxy = 2.0 g/cm3 , and Eepoxy = 500 MPa.

Determine the lower heating value, in kJ per kmol of fuel and in kJ per kg...

Determine the lower heating value, in kJ per kmol of fuel and in kJ per kg of fuel, at 25 oC, 1 atm for \ (a) Gaseous ethane (C2H6). (b) Liquid ethanol (C2H5OH).

1. The value of ΔHo for the reaction below is -228 kJ. Calculate the value of...

1. The value of ΔHo for the reaction below is -228 kJ. Calculate the value of ΔHorxn (in kJ) when 2.59 moles of NaOH (s) is formed in the reaction? 2 Na2O2 (s) + 2 H2O (l) → 4 NaOH (s) + O2 (g) 2.The value of ΔHo for the reaction below is -721 kJ. 2 S (s) + 3 O2 (g) → 2 SO3 (s) amount of heat released during the reaction of 6.64 grams of S (s) is...

14. Consider the following reaction: 2AgCl(s)  2Ag(s) + Cl2(g) H° = 127.1 kJ; S° =...

14. Consider the following reaction: 2AgCl(s)  2Ag(s) + Cl2(g) H° = 127.1 kJ; S° = 115.7 J/K at 298 K Suppose 41.0 g of silver(I) chloride is placed in a 70.0 L vessel at 298 K. When equilibrium is reached, what will the partial pressure of chlorine gas be? (R = 0.0821 L · atm/(K · mol) = 8.31 J/(K · mol)) A) 0.050 atm B) 5.1  10–23 atm C) 0.95 atm D) 0.10 atm E) 5.7 ...

Given the following thermochemical equations, 2Cu(s) + S(s) right-arrow Cu2S(s) ΔH°= –79.5 kJ S(s) + O2(g)...

Given the following thermochemical equations, 2Cu(s) + S(s) right-arrow Cu2S(s) ΔH°= –79.5 kJ S(s) + O2(g) right-arrow SO2(g) ΔH°= –297 kJ Cu2S(s) + 2O2(g) right-arrow 2CuO(s) + SO2(g) ΔH° = –527.5 kJ calculate the standard enthalpy of formation (in kJ mole–1) of CuO(s). Multiplied by 1/2 Finally, using the thermodynamic values given and knowing how to add all the equations together to get the desire equation, calculate the value of ΔHf° for the final formation reaction.

If 11.2 kilograms of Al2O3(s), 52.4 kilograms of NaOH(l), and 52.4 kilograms of HF(g) react completely,...

If 11.2 kilograms of Al2O3(s), 52.4 kilograms of NaOH(l), and 52.4 kilograms of HF(g) react completely, how many kilograms of cryolite will be produced?What is the total mass of the excess reactants left over after the reaction is complete?

Question