Input interpretation
H_2O (water) + I_2 (iodine) + SO_2 (sulfur dioxide) ⟶ H_2SO_4 (sulfuric acid) + HI (hydrogen iodide)
Balanced equation
Balance the chemical equation algebraically: H_2O + I_2 + SO_2 ⟶ H_2SO_4 + HI Add stoichiometric coefficients, c_i, to the reactants and products: c_1 H_2O + c_2 I_2 + c_3 SO_2 ⟶ c_4 H_2SO_4 + c_5 HI Set the number of atoms in the reactants equal to the number of atoms in the products for H, O, I and S: H: | 2 c_1 = 2 c_4 + c_5 O: | c_1 + 2 c_3 = 4 c_4 I: | 2 c_2 = c_5 S: | c_3 = c_4 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_2 = 1 and solve the system of equations for the remaining coefficients: c_1 = 2 c_2 = 1 c_3 = 1 c_4 = 1 c_5 = 2 Substitute the coefficients into the chemical reaction to obtain the balanced equation: Answer: | | 2 H_2O + I_2 + SO_2 ⟶ H_2SO_4 + 2 HI
Structures
+ + ⟶ +
Names
water + iodine + sulfur dioxide ⟶ sulfuric acid + hydrogen iodide
Reaction thermodynamics
Enthalpy
| water | iodine | sulfur dioxide | sulfuric acid | hydrogen iodide molecular enthalpy | -285.8 kJ/mol | 0 kJ/mol | -296.8 kJ/mol | -814 kJ/mol | 26.5 kJ/mol total enthalpy | -571.7 kJ/mol | 0 kJ/mol | -296.8 kJ/mol | -814 kJ/mol | 53 kJ/mol | H_initial = -868.5 kJ/mol | | | H_final = -761 kJ/mol | ΔH_rxn^0 | -761 kJ/mol - -868.5 kJ/mol = 107.5 kJ/mol (endothermic) | | | |
Gibbs free energy
| water | iodine | sulfur dioxide | sulfuric acid | hydrogen iodide molecular free energy | -237.1 kJ/mol | 0 kJ/mol | -300.1 kJ/mol | -690 kJ/mol | 1.7 kJ/mol total free energy | -474.2 kJ/mol | 0 kJ/mol | -300.1 kJ/mol | -690 kJ/mol | 3.4 kJ/mol | G_initial = -774.3 kJ/mol | | | G_final = -686.6 kJ/mol | ΔG_rxn^0 | -686.6 kJ/mol - -774.3 kJ/mol = 87.7 kJ/mol (endergonic) | | | |
Equilibrium constant
![K_c = ([H2SO4] [HI]^2)/([H2O]^2 [I2] [SO2])](../image_source/40d3e922d39c668f4cc5abe361237b2d.png)
K_c = ([H2SO4] [HI]^2)/([H2O]^2 [I2] [SO2])
Rate of reaction
![rate = -1/2 (Δ[H2O])/(Δt) = -(Δ[I2])/(Δt) = -(Δ[SO2])/(Δt) = (Δ[H2SO4])/(Δt) = 1/2 (Δ[HI])/(Δt) (assuming constant volume and no accumulation of intermediates or side products)](../image_source/c06f061b3838151043ab2f1ba0c4e45f.png)
rate = -1/2 (Δ[H2O])/(Δt) = -(Δ[I2])/(Δt) = -(Δ[SO2])/(Δt) = (Δ[H2SO4])/(Δt) = 1/2 (Δ[HI])/(Δt) (assuming constant volume and no accumulation of intermediates or side products)
Chemical names and formulas
| water | iodine | sulfur dioxide | sulfuric acid | hydrogen iodide formula | H_2O | I_2 | SO_2 | H_2SO_4 | HI Hill formula | H_2O | I_2 | O_2S | H_2O_4S | HI name | water | iodine | sulfur dioxide | sulfuric acid | hydrogen iodide IUPAC name | water | molecular iodine | sulfur dioxide | sulfuric acid | hydrogen iodide
Substance properties
| water | iodine | sulfur dioxide | sulfuric acid | hydrogen iodide molar mass | 18.015 g/mol | 253.80894 g/mol | 64.06 g/mol | 98.07 g/mol | 127.912 g/mol phase | liquid (at STP) | solid (at STP) | gas (at STP) | liquid (at STP) | gas (at STP) melting point | 0 °C | 113 °C | -73 °C | 10.371 °C | -50.76 °C boiling point | 99.9839 °C | 184 °C | -10 °C | 279.6 °C | -35.55 °C density | 1 g/cm^3 | 4.94 g/cm^3 | 0.002619 g/cm^3 (at 25 °C) | 1.8305 g/cm^3 | 0.005228 g/cm^3 (at 25 °C) solubility in water | | | | very soluble | very soluble surface tension | 0.0728 N/m | | 0.02859 N/m | 0.0735 N/m | dynamic viscosity | 8.9×10^-4 Pa s (at 25 °C) | 0.00227 Pa s (at 116 °C) | 1.282×10^-5 Pa s (at 25 °C) | 0.021 Pa s (at 25 °C) | 0.001321 Pa s (at -39 °C) odor | odorless | | | odorless |
Units
