Input interpretation
H_2O water + NaOH sodium hydroxide + Zn zinc ⟶ H_2 hydrogen + Na2Zn(OH)4
Balanced equation
Balance the chemical equation algebraically: H_2O + NaOH + Zn ⟶ H_2 + Na2Zn(OH)4 Add stoichiometric coefficients, c_i, to the reactants and products: c_1 H_2O + c_2 NaOH + c_3 Zn ⟶ c_4 H_2 + c_5 Na2Zn(OH)4 Set the number of atoms in the reactants equal to the number of atoms in the products for H, O, Na and Zn: H: | 2 c_1 + c_2 = 2 c_4 + 4 c_5 O: | c_1 + c_2 = 4 c_5 Na: | c_2 = 2 c_5 Zn: | c_3 = c_5 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 = 2 c_2 = 2 c_3 = 1 c_4 = 1 c_5 = 1 Substitute the coefficients into the chemical reaction to obtain the balanced equation: Answer: | | 2 H_2O + 2 NaOH + Zn ⟶ H_2 + Na2Zn(OH)4
Structures
+ + ⟶ + Na2Zn(OH)4
Names
water + sodium hydroxide + zinc ⟶ hydrogen + Na2Zn(OH)4
Equilibrium constant
Construct the equilibrium constant, K, expression for: H_2O + NaOH + Zn ⟶ H_2 + Na2Zn(OH)4 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: 2 H_2O + 2 NaOH + Zn ⟶ H_2 + Na2Zn(OH)4 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 | 2 | -2 NaOH | 2 | -2 Zn | 1 | -1 H_2 | 1 | 1 Na2Zn(OH)4 | 1 | 1 Assemble the activity expressions accounting for the state of matter and ν_i: chemical species | c_i | ν_i | activity expression H_2O | 2 | -2 | ([H2O])^(-2) NaOH | 2 | -2 | ([NaOH])^(-2) Zn | 1 | -1 | ([Zn])^(-1) H_2 | 1 | 1 | [H2] Na2Zn(OH)4 | 1 | 1 | [Na2Zn(OH)4] 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])^(-2) ([NaOH])^(-2) ([Zn])^(-1) [H2] [Na2Zn(OH)4] = ([H2] [Na2Zn(OH)4])/(([H2O])^2 ([NaOH])^2 [Zn])
Rate of reaction
Construct the rate of reaction expression for: H_2O + NaOH + Zn ⟶ H_2 + Na2Zn(OH)4 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: 2 H_2O + 2 NaOH + Zn ⟶ H_2 + Na2Zn(OH)4 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 | 2 | -2 NaOH | 2 | -2 Zn | 1 | -1 H_2 | 1 | 1 Na2Zn(OH)4 | 1 | 1 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 | 2 | -2 | -1/2 (Δ[H2O])/(Δt) NaOH | 2 | -2 | -1/2 (Δ[NaOH])/(Δt) Zn | 1 | -1 | -(Δ[Zn])/(Δt) H_2 | 1 | 1 | (Δ[H2])/(Δt) Na2Zn(OH)4 | 1 | 1 | (Δ[Na2Zn(OH)4])/(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 = -1/2 (Δ[H2O])/(Δt) = -1/2 (Δ[NaOH])/(Δt) = -(Δ[Zn])/(Δt) = (Δ[H2])/(Δt) = (Δ[Na2Zn(OH)4])/(Δt) (assuming constant volume and no accumulation of intermediates or side products)
Chemical names and formulas
| water | sodium hydroxide | zinc | hydrogen | Na2Zn(OH)4 formula | H_2O | NaOH | Zn | H_2 | Na2Zn(OH)4 Hill formula | H_2O | HNaO | Zn | H_2 | H4Na2O4Zn name | water | sodium hydroxide | zinc | hydrogen | IUPAC name | water | sodium hydroxide | zinc | molecular hydrogen |
Substance properties
| water | sodium hydroxide | zinc | hydrogen | Na2Zn(OH)4 molar mass | 18.015 g/mol | 39.997 g/mol | 65.38 g/mol | 2.016 g/mol | 179.4 g/mol phase | liquid (at STP) | solid (at STP) | solid (at STP) | gas (at STP) | melting point | 0 °C | 323 °C | 420 °C | -259.2 °C | boiling point | 99.9839 °C | 1390 °C | 907 °C | -252.8 °C | density | 1 g/cm^3 | 2.13 g/cm^3 | 7.14 g/cm^3 | 8.99×10^-5 g/cm^3 (at 0 °C) | solubility in water | | soluble | insoluble | | surface tension | 0.0728 N/m | 0.07435 N/m | | | dynamic viscosity | 8.9×10^-4 Pa s (at 25 °C) | 0.004 Pa s (at 350 °C) | | 8.9×10^-6 Pa s (at 25 °C) | odor | odorless | | odorless | odorless |
Units