standard enthalpy

What is the standard enthalpy change of formation?

• 2Fe (s) + 1¹/₂O_2(g) → Fe₂O_3(s)

• 4Fe (s) + 3O₂ → 2 Fe₂O_3(s)

• 2H_2(g) + O_{2 (g)} → 2H₂O (l)

Tags

NGSS.HS-PS1-4

Using the equations below:

C_(s) + O_2(g) → CO_2(g) ∆H = –390 kJ

Mn_(s) + O_2(g) → MnO_2(s) ∆H = –520 kJ

what is ∆H (in kJ) for the following reaction?

MnO_2(s) + C_(s) → Mn_(s) + CO_2(g)

• 910

• 130

• -130

• -910

Tags

NGSS.HS-PS1-4

Consider the following equations.

Mg_(s) + O_2(g) → MgO_(s) ∆H = –602 kJ

H_2(g) + O_2(g) → H₂O_(g) ∆H = –242 kJ

What is the ∆H value (in kJ) for the following reaction?

MgO_(s) + H_2(g) → Mg_(s) + H₂O_(g)

• -844

• -360

• +360

• +844

Tags

NGSS.HS-PS1-4

In order to find the enthalpy of combustion of C₃H₈ how must the enthalpy changes be arranged?

• ΔH₃ = ΔH₁ + ΔH₂

• ΔH₂ = ΔH₃ +ΔH₁

• ΔH₁ = ΔH₂ - ΔH₃

• 0 = ΔH₁ + ΔH₂ + ΔH₃

Elements in their standard state always have standard enthalpies of ________.

• -396 kJ/mol

• 33.2 kJ/mol

• 0.0 kJ/mol

• 396 kJ/mol

Calculate ΔH° for the following reaction. The standard enthalpies of formation for the two reactants and two products are, in order, -1118, -110.5, -272, -393.5 (all in kJ/mol)

Fe₃O₄(s) + CO(g) →3FeO(s) + CO₂(g)

• -263 kJ

• 54 kJ

• 19 kJ

• -50 kJ

Calculate the enthalpy of reaction (ΔH).

4CO_{2 (g)} + 6H₂O _(g) → 2C₂H_{6 (g)} + 7O_{2 (g)}

ΔH_f^o [CO_2(g)] = -393.5 kJ

ΔH_f^o [H₂O_(g)] = -241.8 kJ

ΔH_f^o [C₂H_6(g)] = -84.7 kJ

• 550.6 kJ/mol

• 2855.4 kJ/mol

• -550.6 kJ/mol

• -3194.2 kJ/mol