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H2O + KI + Na2Cr2O7 = NaOH + KOH + I2 + Cr(OH)3

Input interpretation

H_2O water + KI potassium iodide + Na_2Cr_2O_7 sodium bichromate ⟶ NaOH sodium hydroxide + KOH potassium hydroxide + I_2 iodine + Cr(OH)3
H_2O water + KI potassium iodide + Na_2Cr_2O_7 sodium bichromate ⟶ NaOH sodium hydroxide + KOH potassium hydroxide + I_2 iodine + Cr(OH)3

Balanced equation

Balance the chemical equation algebraically: H_2O + KI + Na_2Cr_2O_7 ⟶ NaOH + KOH + I_2 + Cr(OH)3 Add stoichiometric coefficients, c_i, to the reactants and products: c_1 H_2O + c_2 KI + c_3 Na_2Cr_2O_7 ⟶ c_4 NaOH + c_5 KOH + c_6 I_2 + c_7 Cr(OH)3 Set the number of atoms in the reactants equal to the number of atoms in the products for H, O, I, K, Cr and Na: H: | 2 c_1 = c_4 + c_5 + 3 c_7 O: | c_1 + 7 c_3 = c_4 + c_5 + 3 c_7 I: | c_2 = 2 c_6 K: | c_2 = c_5 Cr: | 2 c_3 = c_7 Na: | 2 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_3 = 1 and solve the system of equations for the remaining coefficients: c_1 = 7 c_2 = 6 c_3 = 1 c_4 = 2 c_5 = 6 c_6 = 3 c_7 = 2 Substitute the coefficients into the chemical reaction to obtain the balanced equation: Answer: |   | 7 H_2O + 6 KI + Na_2Cr_2O_7 ⟶ 2 NaOH + 6 KOH + 3 I_2 + 2 Cr(OH)3
Balance the chemical equation algebraically: H_2O + KI + Na_2Cr_2O_7 ⟶ NaOH + KOH + I_2 + Cr(OH)3 Add stoichiometric coefficients, c_i, to the reactants and products: c_1 H_2O + c_2 KI + c_3 Na_2Cr_2O_7 ⟶ c_4 NaOH + c_5 KOH + c_6 I_2 + c_7 Cr(OH)3 Set the number of atoms in the reactants equal to the number of atoms in the products for H, O, I, K, Cr and Na: H: | 2 c_1 = c_4 + c_5 + 3 c_7 O: | c_1 + 7 c_3 = c_4 + c_5 + 3 c_7 I: | c_2 = 2 c_6 K: | c_2 = c_5 Cr: | 2 c_3 = c_7 Na: | 2 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_3 = 1 and solve the system of equations for the remaining coefficients: c_1 = 7 c_2 = 6 c_3 = 1 c_4 = 2 c_5 = 6 c_6 = 3 c_7 = 2 Substitute the coefficients into the chemical reaction to obtain the balanced equation: Answer: | | 7 H_2O + 6 KI + Na_2Cr_2O_7 ⟶ 2 NaOH + 6 KOH + 3 I_2 + 2 Cr(OH)3

Structures

 + + ⟶ + + + Cr(OH)3
+ + ⟶ + + + Cr(OH)3

Names

water + potassium iodide + sodium bichromate ⟶ sodium hydroxide + potassium hydroxide + iodine + Cr(OH)3
water + potassium iodide + sodium bichromate ⟶ sodium hydroxide + potassium hydroxide + iodine + Cr(OH)3

Equilibrium constant

Construct the equilibrium constant, K, expression for: H_2O + KI + Na_2Cr_2O_7 ⟶ NaOH + KOH + I_2 + Cr(OH)3 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: 7 H_2O + 6 KI + Na_2Cr_2O_7 ⟶ 2 NaOH + 6 KOH + 3 I_2 + 2 Cr(OH)3 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 H_2O | 7 | -7 KI | 6 | -6 Na_2Cr_2O_7 | 1 | -1 NaOH | 2 | 2 KOH | 6 | 6 I_2 | 3 | 3 Cr(OH)3 | 2 | 2 Assemble the activity expressions accounting for the state of matter and ν_i: chemical species | c_i | ν_i | activity expression H_2O | 7 | -7 | ([H2O])^(-7) KI | 6 | -6 | ([KI])^(-6) Na_2Cr_2O_7 | 1 | -1 | ([Na2Cr2O7])^(-1) NaOH | 2 | 2 | ([NaOH])^2 KOH | 6 | 6 | ([KOH])^6 I_2 | 3 | 3 | ([I2])^3 Cr(OH)3 | 2 | 2 | ([Cr(OH)3])^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 = ([H2O])^(-7) ([KI])^(-6) ([Na2Cr2O7])^(-1) ([NaOH])^2 ([KOH])^6 ([I2])^3 ([Cr(OH)3])^2 = (([NaOH])^2 ([KOH])^6 ([I2])^3 ([Cr(OH)3])^2)/(([H2O])^7 ([KI])^6 [Na2Cr2O7])
Construct the equilibrium constant, K, expression for: H_2O + KI + Na_2Cr_2O_7 ⟶ NaOH + KOH + I_2 + Cr(OH)3 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: 7 H_2O + 6 KI + Na_2Cr_2O_7 ⟶ 2 NaOH + 6 KOH + 3 I_2 + 2 Cr(OH)3 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 H_2O | 7 | -7 KI | 6 | -6 Na_2Cr_2O_7 | 1 | -1 NaOH | 2 | 2 KOH | 6 | 6 I_2 | 3 | 3 Cr(OH)3 | 2 | 2 Assemble the activity expressions accounting for the state of matter and ν_i: chemical species | c_i | ν_i | activity expression H_2O | 7 | -7 | ([H2O])^(-7) KI | 6 | -6 | ([KI])^(-6) Na_2Cr_2O_7 | 1 | -1 | ([Na2Cr2O7])^(-1) NaOH | 2 | 2 | ([NaOH])^2 KOH | 6 | 6 | ([KOH])^6 I_2 | 3 | 3 | ([I2])^3 Cr(OH)3 | 2 | 2 | ([Cr(OH)3])^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 = ([H2O])^(-7) ([KI])^(-6) ([Na2Cr2O7])^(-1) ([NaOH])^2 ([KOH])^6 ([I2])^3 ([Cr(OH)3])^2 = (([NaOH])^2 ([KOH])^6 ([I2])^3 ([Cr(OH)3])^2)/(([H2O])^7 ([KI])^6 [Na2Cr2O7])

Rate of reaction

Construct the rate of reaction expression for: H_2O + KI + Na_2Cr_2O_7 ⟶ NaOH + KOH + I_2 + Cr(OH)3 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: 7 H_2O + 6 KI + Na_2Cr_2O_7 ⟶ 2 NaOH + 6 KOH + 3 I_2 + 2 Cr(OH)3 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 H_2O | 7 | -7 KI | 6 | -6 Na_2Cr_2O_7 | 1 | -1 NaOH | 2 | 2 KOH | 6 | 6 I_2 | 3 | 3 Cr(OH)3 | 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 H_2O | 7 | -7 | -1/7 (Δ[H2O])/(Δt) KI | 6 | -6 | -1/6 (Δ[KI])/(Δt) Na_2Cr_2O_7 | 1 | -1 | -(Δ[Na2Cr2O7])/(Δt) NaOH | 2 | 2 | 1/2 (Δ[NaOH])/(Δt) KOH | 6 | 6 | 1/6 (Δ[KOH])/(Δt) I_2 | 3 | 3 | 1/3 (Δ[I2])/(Δt) Cr(OH)3 | 2 | 2 | 1/2 (Δ[Cr(OH)3])/(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 = -1/7 (Δ[H2O])/(Δt) = -1/6 (Δ[KI])/(Δt) = -(Δ[Na2Cr2O7])/(Δt) = 1/2 (Δ[NaOH])/(Δt) = 1/6 (Δ[KOH])/(Δt) = 1/3 (Δ[I2])/(Δt) = 1/2 (Δ[Cr(OH)3])/(Δt) (assuming constant volume and no accumulation of intermediates or side products)
Construct the rate of reaction expression for: H_2O + KI + Na_2Cr_2O_7 ⟶ NaOH + KOH + I_2 + Cr(OH)3 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: 7 H_2O + 6 KI + Na_2Cr_2O_7 ⟶ 2 NaOH + 6 KOH + 3 I_2 + 2 Cr(OH)3 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 H_2O | 7 | -7 KI | 6 | -6 Na_2Cr_2O_7 | 1 | -1 NaOH | 2 | 2 KOH | 6 | 6 I_2 | 3 | 3 Cr(OH)3 | 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 H_2O | 7 | -7 | -1/7 (Δ[H2O])/(Δt) KI | 6 | -6 | -1/6 (Δ[KI])/(Δt) Na_2Cr_2O_7 | 1 | -1 | -(Δ[Na2Cr2O7])/(Δt) NaOH | 2 | 2 | 1/2 (Δ[NaOH])/(Δt) KOH | 6 | 6 | 1/6 (Δ[KOH])/(Δt) I_2 | 3 | 3 | 1/3 (Δ[I2])/(Δt) Cr(OH)3 | 2 | 2 | 1/2 (Δ[Cr(OH)3])/(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 = -1/7 (Δ[H2O])/(Δt) = -1/6 (Δ[KI])/(Δt) = -(Δ[Na2Cr2O7])/(Δt) = 1/2 (Δ[NaOH])/(Δt) = 1/6 (Δ[KOH])/(Δt) = 1/3 (Δ[I2])/(Δt) = 1/2 (Δ[Cr(OH)3])/(Δt) (assuming constant volume and no accumulation of intermediates or side products)

Chemical names and formulas

 | water | potassium iodide | sodium bichromate | sodium hydroxide | potassium hydroxide | iodine | Cr(OH)3 formula | H_2O | KI | Na_2Cr_2O_7 | NaOH | KOH | I_2 | Cr(OH)3 Hill formula | H_2O | IK | Cr_2Na_2O_7 | HNaO | HKO | I_2 | H3CrO3 name | water | potassium iodide | sodium bichromate | sodium hydroxide | potassium hydroxide | iodine |  IUPAC name | water | potassium iodide | disodium oxido-(oxido-dioxo-chromio)oxy-dioxo-chromium | sodium hydroxide | potassium hydroxide | molecular iodine |
| water | potassium iodide | sodium bichromate | sodium hydroxide | potassium hydroxide | iodine | Cr(OH)3 formula | H_2O | KI | Na_2Cr_2O_7 | NaOH | KOH | I_2 | Cr(OH)3 Hill formula | H_2O | IK | Cr_2Na_2O_7 | HNaO | HKO | I_2 | H3CrO3 name | water | potassium iodide | sodium bichromate | sodium hydroxide | potassium hydroxide | iodine | IUPAC name | water | potassium iodide | disodium oxido-(oxido-dioxo-chromio)oxy-dioxo-chromium | sodium hydroxide | potassium hydroxide | molecular iodine |

Substance properties

 | water | potassium iodide | sodium bichromate | sodium hydroxide | potassium hydroxide | iodine | Cr(OH)3 molar mass | 18.015 g/mol | 166.0028 g/mol | 261.96 g/mol | 39.997 g/mol | 56.105 g/mol | 253.80894 g/mol | 103.02 g/mol phase | liquid (at STP) | solid (at STP) | solid (at STP) | solid (at STP) | solid (at STP) | solid (at STP) |  melting point | 0 °C | 681 °C | 356.7 °C | 323 °C | 406 °C | 113 °C |  boiling point | 99.9839 °C | 1330 °C | | 1390 °C | 1327 °C | 184 °C |  density | 1 g/cm^3 | 3.123 g/cm^3 | 2.35 g/cm^3 | 2.13 g/cm^3 | 2.044 g/cm^3 | 4.94 g/cm^3 |  solubility in water | | | | soluble | soluble | |  surface tension | 0.0728 N/m | | | 0.07435 N/m | | |  dynamic viscosity | 8.9×10^-4 Pa s (at 25 °C) | 0.0010227 Pa s (at 732.9 °C) | | 0.004 Pa s (at 350 °C) | 0.001 Pa s (at 550 °C) | 0.00227 Pa s (at 116 °C) |  odor | odorless | | | | | |
| water | potassium iodide | sodium bichromate | sodium hydroxide | potassium hydroxide | iodine | Cr(OH)3 molar mass | 18.015 g/mol | 166.0028 g/mol | 261.96 g/mol | 39.997 g/mol | 56.105 g/mol | 253.80894 g/mol | 103.02 g/mol phase | liquid (at STP) | solid (at STP) | solid (at STP) | solid (at STP) | solid (at STP) | solid (at STP) | melting point | 0 °C | 681 °C | 356.7 °C | 323 °C | 406 °C | 113 °C | boiling point | 99.9839 °C | 1330 °C | | 1390 °C | 1327 °C | 184 °C | density | 1 g/cm^3 | 3.123 g/cm^3 | 2.35 g/cm^3 | 2.13 g/cm^3 | 2.044 g/cm^3 | 4.94 g/cm^3 | solubility in water | | | | soluble | soluble | | surface tension | 0.0728 N/m | | | 0.07435 N/m | | | dynamic viscosity | 8.9×10^-4 Pa s (at 25 °C) | 0.0010227 Pa s (at 732.9 °C) | | 0.004 Pa s (at 350 °C) | 0.001 Pa s (at 550 °C) | 0.00227 Pa s (at 116 °C) | odor | odorless | | | | | |

Units