Enthalpies of Formation and Reaction 10.2

Enthalpy (H)

When finding the enthalpy change from enthalpies of formation, the formula is...

What is ∆H (in kJ) for the following reaction? MnO₂(s) + C(s) → Mn_(s) + CO₂(g)

Using the equations below (remember if an equation needs to flip change the sign of the ∆H ):

C(s) + O₂(g) → CO₂(g) ∆H = –390 kJ

Mn(s) + O₂(g) → MnO₂(s) ∆H = –520 kJ

The following equations show the oxidation of carbon and carbon monoxide to carbon dioxide.

C(s) +O₂(g) → CO₂(g) ΔH = –x kJ/mol

CO(g) + O₂(g) → CO₂(g) ΔH = –y kJ/mol

What is the enthalpy change, in kJ/mol, for the oxidation of carbon to carbon monoxide?

C(s) + O₂(g) → CO(g)

What is the ∆H value (in kJ) for the following reaction: MgO(s) + H₂(g₎ → Mg(s) + H₂O(g)

Consider the following equations.

Mg(s) + O₂(g) → MgO(s) ∆H = –602 kJ

H₂(g) + O₂(g) → H₂O(g) ∆H = –242 kJ

What is the phase of hydrogen and oxygen at standard state? (25°C is about room temperature)

Which type of reaction is referred to in the definition of standard enthalpy change of formation?

What is the standard heat of formation of 4 moles of SO₂ at 296.8 kJ/mol?

If the energy of formation of the reactants is 297 kJ and the energy of formation of the products is 233 kJ,
what is the standard enthalpy of the reaction?

How much energy is required to turn 1 mole of N₂O₄ (g) into
2 moles N (g) & 4 moles O (g)? [Read the arrows]

If N₂ (g) + 2O₂ (g) $$\longrightarrow$$   2NO₂(g) has a $$\Delta H_{rxn\ }$$  = 68,
then what is the $$\Delta H_{rxn}$$  if you reverse the reaction?

Calculate the following enthalpy of the following reaction: 2Mg + O₂ --> 2MgO

Mg : ΔHf = 0kJ/mol

O₂ : ΔHf = 0J/mol

MgO : ΔHf =-601.6 kJ/mol

What is the enthalpy change for the reaction:   4C(g) + 5H₂(l) + ½O₂(g)   --->   C₄H₉OH(L)

The enthalpies of combustion of C(s), H₂(g) and C4H9OH(l) (in kJ/mol) are as follows:

C(s) + O₂(g)   --->  CO₂(g)    ∆H=a

H₂(g) + ½O₂(g)   --->   H₂O(L)   ∆H=b

C₄H₉OH(l) + 6O₂(g)   --->   4CO₂(g) + 5H₂O(L)  ∆H=c

[You can multiply or divide reactions by a value as long as you do the same to ∆H]

Which of the following represent enthalpy change of solution?

What is the enthalpy change, in kJ mol^–1, for the reaction: P₄O_6(s) + 2O₂(g) → P₄O₁₀(s)

The standard enthalpy change of formation values of two oxides of phosphorus are:

[Yes, you can cancel part of the exponent based on how many are across the -->]

P₄(s) + 3O₂(g₎ → P₄O₆(s) ΔH_f = –1600 kJ mol^–1

P₄(s) + 5O₂(g) → P₄O₁₀(s) ΔH_f = –3000 kJ mol^–1

A chemical reaction that requires energy is a(n)