Input interpretation
![O_2 oxygen + HBr hydrogen bromide ⟶ H_2O water + Br_2 bromine](../image_source/09649b8e353f788b4778ffc6e63813cd.png)
O_2 oxygen + HBr hydrogen bromide ⟶ H_2O water + Br_2 bromine
Balanced equation
![Balance the chemical equation algebraically: O_2 + HBr ⟶ H_2O + Br_2 Add stoichiometric coefficients, c_i, to the reactants and products: c_1 O_2 + c_2 HBr ⟶ c_3 H_2O + c_4 Br_2 Set the number of atoms in the reactants equal to the number of atoms in the products for O, Br and H: O: | 2 c_1 = c_3 Br: | c_2 = 2 c_4 H: | c_2 = 2 c_3 Since the coefficients are relative quantities and underdetermined, choose a coefficient to set arbitrarily. To keep the coefficients small, the arbitrary value is ordinarily one. For instance, set c_1 = 1 and solve the system of equations for the remaining coefficients: c_1 = 1 c_2 = 4 c_3 = 2 c_4 = 2 Substitute the coefficients into the chemical reaction to obtain the balanced equation: Answer: | | O_2 + 4 HBr ⟶ 2 H_2O + 2 Br_2](../image_source/ba730e21fcaf7063a9ec901bcba6f1d0.png)
Balance the chemical equation algebraically: O_2 + HBr ⟶ H_2O + Br_2 Add stoichiometric coefficients, c_i, to the reactants and products: c_1 O_2 + c_2 HBr ⟶ c_3 H_2O + c_4 Br_2 Set the number of atoms in the reactants equal to the number of atoms in the products for O, Br and H: O: | 2 c_1 = c_3 Br: | c_2 = 2 c_4 H: | c_2 = 2 c_3 Since the coefficients are relative quantities and underdetermined, choose a coefficient to set arbitrarily. To keep the coefficients small, the arbitrary value is ordinarily one. For instance, set c_1 = 1 and solve the system of equations for the remaining coefficients: c_1 = 1 c_2 = 4 c_3 = 2 c_4 = 2 Substitute the coefficients into the chemical reaction to obtain the balanced equation: Answer: | | O_2 + 4 HBr ⟶ 2 H_2O + 2 Br_2
Structures
![+ ⟶ +](../image_source/d8ba95108ac414bd8bf6de669701ddde.png)
+ ⟶ +
Names
![oxygen + hydrogen bromide ⟶ water + bromine](../image_source/5ed6db4ef6fdd566674935d2e6d6c5ae.png)
oxygen + hydrogen bromide ⟶ water + bromine
Reaction thermodynamics
Enthalpy
![| oxygen | hydrogen bromide | water | bromine molecular enthalpy | 0 kJ/mol | -36.3 kJ/mol | -285.8 kJ/mol | 0 kJ/mol total enthalpy | 0 kJ/mol | -145.2 kJ/mol | -571.7 kJ/mol | 0 kJ/mol | H_initial = -145.2 kJ/mol | | H_final = -571.7 kJ/mol | ΔH_rxn^0 | -571.7 kJ/mol - -145.2 kJ/mol = -426.5 kJ/mol (exothermic) | | |](../image_source/5730af5eb3a77ec33aa5eebca0651505.png)
| oxygen | hydrogen bromide | water | bromine molecular enthalpy | 0 kJ/mol | -36.3 kJ/mol | -285.8 kJ/mol | 0 kJ/mol total enthalpy | 0 kJ/mol | -145.2 kJ/mol | -571.7 kJ/mol | 0 kJ/mol | H_initial = -145.2 kJ/mol | | H_final = -571.7 kJ/mol | ΔH_rxn^0 | -571.7 kJ/mol - -145.2 kJ/mol = -426.5 kJ/mol (exothermic) | | |
Gibbs free energy
![| oxygen | hydrogen bromide | water | bromine molecular free energy | 231.7 kJ/mol | -53.4 kJ/mol | -237.1 kJ/mol | 0 kJ/mol total free energy | 231.7 kJ/mol | -213.6 kJ/mol | -474.2 kJ/mol | 0 kJ/mol | G_initial = 18.1 kJ/mol | | G_final = -474.2 kJ/mol | ΔG_rxn^0 | -474.2 kJ/mol - 18.1 kJ/mol = -492.3 kJ/mol (exergonic) | | |](../image_source/63dfa258ec690ad32e53a81560549142.png)
| oxygen | hydrogen bromide | water | bromine molecular free energy | 231.7 kJ/mol | -53.4 kJ/mol | -237.1 kJ/mol | 0 kJ/mol total free energy | 231.7 kJ/mol | -213.6 kJ/mol | -474.2 kJ/mol | 0 kJ/mol | G_initial = 18.1 kJ/mol | | G_final = -474.2 kJ/mol | ΔG_rxn^0 | -474.2 kJ/mol - 18.1 kJ/mol = -492.3 kJ/mol (exergonic) | | |
Entropy
![| oxygen | hydrogen bromide | water | bromine molecular entropy | 205 J/(mol K) | 199 J/(mol K) | 69.91 J/(mol K) | 152.2 J/(mol K) total entropy | 205 J/(mol K) | 796 J/(mol K) | 139.8 J/(mol K) | 304.5 J/(mol K) | S_initial = 1001 J/(mol K) | | S_final = 444.3 J/(mol K) | ΔS_rxn^0 | 444.3 J/(mol K) - 1001 J/(mol K) = -556.7 J/(mol K) (exoentropic) | | |](../image_source/de4e9b48c494c8711f596c6999d7415f.png)
| oxygen | hydrogen bromide | water | bromine molecular entropy | 205 J/(mol K) | 199 J/(mol K) | 69.91 J/(mol K) | 152.2 J/(mol K) total entropy | 205 J/(mol K) | 796 J/(mol K) | 139.8 J/(mol K) | 304.5 J/(mol K) | S_initial = 1001 J/(mol K) | | S_final = 444.3 J/(mol K) | ΔS_rxn^0 | 444.3 J/(mol K) - 1001 J/(mol K) = -556.7 J/(mol K) (exoentropic) | | |
Equilibrium constant
![Construct the equilibrium constant, K, expression for: O_2 + HBr ⟶ H_2O + Br_2 Plan: • Balance the chemical equation. • Determine the stoichiometric numbers. • Assemble the activity expression for each chemical species. • Use the activity expressions to build the equilibrium constant expression. Write the balanced chemical equation: O_2 + 4 HBr ⟶ 2 H_2O + 2 Br_2 Assign stoichiometric numbers, ν_i, using the stoichiometric coefficients, c_i, from the balanced chemical equation in the following manner: ν_i = -c_i for reactants and ν_i = c_i for products: chemical species | c_i | ν_i O_2 | 1 | -1 HBr | 4 | -4 H_2O | 2 | 2 Br_2 | 2 | 2 Assemble the activity expressions accounting for the state of matter and ν_i: chemical species | c_i | ν_i | activity expression O_2 | 1 | -1 | ([O2])^(-1) HBr | 4 | -4 | ([HBr])^(-4) H_2O | 2 | 2 | ([H2O])^2 Br_2 | 2 | 2 | ([Br2])^2 The equilibrium constant symbol in the concentration basis is: K_c Mulitply the activity expressions to arrive at the K_c expression: Answer: | | K_c = ([O2])^(-1) ([HBr])^(-4) ([H2O])^2 ([Br2])^2 = (([H2O])^2 ([Br2])^2)/([O2] ([HBr])^4)](../image_source/275aac32bafa234b2619f5f14163c6d0.png)
Construct the equilibrium constant, K, expression for: O_2 + HBr ⟶ H_2O + Br_2 Plan: • Balance the chemical equation. • Determine the stoichiometric numbers. • Assemble the activity expression for each chemical species. • Use the activity expressions to build the equilibrium constant expression. Write the balanced chemical equation: O_2 + 4 HBr ⟶ 2 H_2O + 2 Br_2 Assign stoichiometric numbers, ν_i, using the stoichiometric coefficients, c_i, from the balanced chemical equation in the following manner: ν_i = -c_i for reactants and ν_i = c_i for products: chemical species | c_i | ν_i O_2 | 1 | -1 HBr | 4 | -4 H_2O | 2 | 2 Br_2 | 2 | 2 Assemble the activity expressions accounting for the state of matter and ν_i: chemical species | c_i | ν_i | activity expression O_2 | 1 | -1 | ([O2])^(-1) HBr | 4 | -4 | ([HBr])^(-4) H_2O | 2 | 2 | ([H2O])^2 Br_2 | 2 | 2 | ([Br2])^2 The equilibrium constant symbol in the concentration basis is: K_c Mulitply the activity expressions to arrive at the K_c expression: Answer: | | K_c = ([O2])^(-1) ([HBr])^(-4) ([H2O])^2 ([Br2])^2 = (([H2O])^2 ([Br2])^2)/([O2] ([HBr])^4)
Rate of reaction
![Construct the rate of reaction expression for: O_2 + HBr ⟶ H_2O + Br_2 Plan: • Balance the chemical equation. • Determine the stoichiometric numbers. • Assemble the rate term for each chemical species. • Write the rate of reaction expression. Write the balanced chemical equation: O_2 + 4 HBr ⟶ 2 H_2O + 2 Br_2 Assign stoichiometric numbers, ν_i, using the stoichiometric coefficients, c_i, from the balanced chemical equation in the following manner: ν_i = -c_i for reactants and ν_i = c_i for products: chemical species | c_i | ν_i O_2 | 1 | -1 HBr | 4 | -4 H_2O | 2 | 2 Br_2 | 2 | 2 The rate term for each chemical species, B_i, is 1/ν_i(Δ[B_i])/(Δt) where [B_i] is the amount concentration and t is time: chemical species | c_i | ν_i | rate term O_2 | 1 | -1 | -(Δ[O2])/(Δt) HBr | 4 | -4 | -1/4 (Δ[HBr])/(Δt) H_2O | 2 | 2 | 1/2 (Δ[H2O])/(Δt) Br_2 | 2 | 2 | 1/2 (Δ[Br2])/(Δt) (for infinitesimal rate of change, replace Δ with d) Set the rate terms equal to each other to arrive at the rate expression: Answer: | | rate = -(Δ[O2])/(Δt) = -1/4 (Δ[HBr])/(Δt) = 1/2 (Δ[H2O])/(Δt) = 1/2 (Δ[Br2])/(Δt) (assuming constant volume and no accumulation of intermediates or side products)](../image_source/c47aa70e2d304fd3d49c6af7bddea2f7.png)
Construct the rate of reaction expression for: O_2 + HBr ⟶ H_2O + Br_2 Plan: • Balance the chemical equation. • Determine the stoichiometric numbers. • Assemble the rate term for each chemical species. • Write the rate of reaction expression. Write the balanced chemical equation: O_2 + 4 HBr ⟶ 2 H_2O + 2 Br_2 Assign stoichiometric numbers, ν_i, using the stoichiometric coefficients, c_i, from the balanced chemical equation in the following manner: ν_i = -c_i for reactants and ν_i = c_i for products: chemical species | c_i | ν_i O_2 | 1 | -1 HBr | 4 | -4 H_2O | 2 | 2 Br_2 | 2 | 2 The rate term for each chemical species, B_i, is 1/ν_i(Δ[B_i])/(Δt) where [B_i] is the amount concentration and t is time: chemical species | c_i | ν_i | rate term O_2 | 1 | -1 | -(Δ[O2])/(Δt) HBr | 4 | -4 | -1/4 (Δ[HBr])/(Δt) H_2O | 2 | 2 | 1/2 (Δ[H2O])/(Δt) Br_2 | 2 | 2 | 1/2 (Δ[Br2])/(Δt) (for infinitesimal rate of change, replace Δ with d) Set the rate terms equal to each other to arrive at the rate expression: Answer: | | rate = -(Δ[O2])/(Δt) = -1/4 (Δ[HBr])/(Δt) = 1/2 (Δ[H2O])/(Δt) = 1/2 (Δ[Br2])/(Δt) (assuming constant volume and no accumulation of intermediates or side products)
Chemical names and formulas
![| oxygen | hydrogen bromide | water | bromine formula | O_2 | HBr | H_2O | Br_2 Hill formula | O_2 | BrH | H_2O | Br_2 name | oxygen | hydrogen bromide | water | bromine IUPAC name | molecular oxygen | hydrogen bromide | water | molecular bromine](../image_source/1c69f901b1d1fea42742c1300e8f4bf7.png)
| oxygen | hydrogen bromide | water | bromine formula | O_2 | HBr | H_2O | Br_2 Hill formula | O_2 | BrH | H_2O | Br_2 name | oxygen | hydrogen bromide | water | bromine IUPAC name | molecular oxygen | hydrogen bromide | water | molecular bromine
Substance properties
![| oxygen | hydrogen bromide | water | bromine molar mass | 31.998 g/mol | 80.912 g/mol | 18.015 g/mol | 159.81 g/mol phase | gas (at STP) | gas (at STP) | liquid (at STP) | liquid (at STP) melting point | -218 °C | -86.8 °C | 0 °C | -7.2 °C boiling point | -183 °C | -66.38 °C | 99.9839 °C | 58.8 °C density | 0.001429 g/cm^3 (at 0 °C) | 0.003307 g/cm^3 (at 25 °C) | 1 g/cm^3 | 3.119 g/cm^3 solubility in water | | miscible | | insoluble surface tension | 0.01347 N/m | 0.0271 N/m | 0.0728 N/m | 0.0409 N/m dynamic viscosity | 2.055×10^-5 Pa s (at 25 °C) | 8.4×10^-4 Pa s (at -75 °C) | 8.9×10^-4 Pa s (at 25 °C) | 9.44×10^-4 Pa s (at 25 °C) odor | odorless | | odorless |](../image_source/05c1174dc11b6cb5ca846f8eaff24488.png)
| oxygen | hydrogen bromide | water | bromine molar mass | 31.998 g/mol | 80.912 g/mol | 18.015 g/mol | 159.81 g/mol phase | gas (at STP) | gas (at STP) | liquid (at STP) | liquid (at STP) melting point | -218 °C | -86.8 °C | 0 °C | -7.2 °C boiling point | -183 °C | -66.38 °C | 99.9839 °C | 58.8 °C density | 0.001429 g/cm^3 (at 0 °C) | 0.003307 g/cm^3 (at 25 °C) | 1 g/cm^3 | 3.119 g/cm^3 solubility in water | | miscible | | insoluble surface tension | 0.01347 N/m | 0.0271 N/m | 0.0728 N/m | 0.0409 N/m dynamic viscosity | 2.055×10^-5 Pa s (at 25 °C) | 8.4×10^-4 Pa s (at -75 °C) | 8.9×10^-4 Pa s (at 25 °C) | 9.44×10^-4 Pa s (at 25 °C) odor | odorless | | odorless |
Units