Input interpretation
NaOH sodium hydroxide + (HO)_2P(O)OP(O)(OH)_2 pyrophosphoric acid ⟶ H_2O water + Na_4O_7P_2 sodium pyrophosphate
Balanced equation
Balance the chemical equation algebraically: NaOH + (HO)_2P(O)OP(O)(OH)_2 ⟶ H_2O + Na_4O_7P_2 Add stoichiometric coefficients, c_i, to the reactants and products: c_1 NaOH + c_2 (HO)_2P(O)OP(O)(OH)_2 ⟶ c_3 H_2O + c_4 Na_4O_7P_2 Set the number of atoms in the reactants equal to the number of atoms in the products for H, Na, O and P: H: | c_1 + 4 c_2 = 2 c_3 Na: | c_1 = 4 c_4 O: | c_1 + 7 c_2 = c_3 + 7 c_4 P: | 2 c_2 = 2 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 = 4 c_2 = 1 c_3 = 4 c_4 = 1 Substitute the coefficients into the chemical reaction to obtain the balanced equation: Answer: | | 4 NaOH + (HO)_2P(O)OP(O)(OH)_2 ⟶ 4 H_2O + Na_4O_7P_2
Structures
+ ⟶ +
Names
sodium hydroxide + pyrophosphoric acid ⟶ water + sodium pyrophosphate
Equilibrium constant
Construct the equilibrium constant, K, expression for: NaOH + (HO)_2P(O)OP(O)(OH)_2 ⟶ H_2O + Na_4O_7P_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: 4 NaOH + (HO)_2P(O)OP(O)(OH)_2 ⟶ 4 H_2O + Na_4O_7P_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 NaOH | 4 | -4 (HO)_2P(O)OP(O)(OH)_2 | 1 | -1 H_2O | 4 | 4 Na_4O_7P_2 | 1 | 1 Assemble the activity expressions accounting for the state of matter and ν_i: chemical species | c_i | ν_i | activity expression NaOH | 4 | -4 | ([NaOH])^(-4) (HO)_2P(O)OP(O)(OH)_2 | 1 | -1 | ([(HO)2P(O)OP(O)(OH)2])^(-1) H_2O | 4 | 4 | ([H2O])^4 Na_4O_7P_2 | 1 | 1 | [Na4O7P2] 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 = ([NaOH])^(-4) ([(HO)2P(O)OP(O)(OH)2])^(-1) ([H2O])^4 [Na4O7P2] = (([H2O])^4 [Na4O7P2])/(([NaOH])^4 [(HO)2P(O)OP(O)(OH)2])
Rate of reaction
Construct the rate of reaction expression for: NaOH + (HO)_2P(O)OP(O)(OH)_2 ⟶ H_2O + Na_4O_7P_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: 4 NaOH + (HO)_2P(O)OP(O)(OH)_2 ⟶ 4 H_2O + Na_4O_7P_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 NaOH | 4 | -4 (HO)_2P(O)OP(O)(OH)_2 | 1 | -1 H_2O | 4 | 4 Na_4O_7P_2 | 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 NaOH | 4 | -4 | -1/4 (Δ[NaOH])/(Δt) (HO)_2P(O)OP(O)(OH)_2 | 1 | -1 | -(Δ[(HO)2P(O)OP(O)(OH)2])/(Δt) H_2O | 4 | 4 | 1/4 (Δ[H2O])/(Δt) Na_4O_7P_2 | 1 | 1 | (Δ[Na4O7P2])/(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 = -1/4 (Δ[NaOH])/(Δt) = -(Δ[(HO)2P(O)OP(O)(OH)2])/(Δt) = 1/4 (Δ[H2O])/(Δt) = (Δ[Na4O7P2])/(Δt) (assuming constant volume and no accumulation of intermediates or side products)
Chemical names and formulas
| sodium hydroxide | pyrophosphoric acid | water | sodium pyrophosphate formula | NaOH | (HO)_2P(O)OP(O)(OH)_2 | H_2O | Na_4O_7P_2 Hill formula | HNaO | H_4O_7P_2 | H_2O | Na_4O_7P_2 name | sodium hydroxide | pyrophosphoric acid | water | sodium pyrophosphate IUPAC name | sodium hydroxide | phosphono dihydrogen phosphate | water | tetrasodium dioxido-oxo-phosphonatooxy-phosphorane
Substance properties
| sodium hydroxide | pyrophosphoric acid | water | sodium pyrophosphate molar mass | 39.997 g/mol | 177.97 g/mol | 18.015 g/mol | 265.9 g/mol phase | solid (at STP) | solid (at STP) | liquid (at STP) | solid (at STP) melting point | 323 °C | 61 °C | 0 °C | 988 °C boiling point | 1390 °C | | 99.9839 °C | density | 2.13 g/cm^3 | 1.75 g/cm^3 | 1 g/cm^3 | 2.534 g/cm^3 solubility in water | soluble | very soluble | | surface tension | 0.07435 N/m | | 0.0728 N/m | dynamic viscosity | 0.004 Pa s (at 350 °C) | 0.62 Pa s (at 25 °C) | 8.9×10^-4 Pa s (at 25 °C) | odor | | | odorless |
Units