H2O + Cs2O = CsOH

H_2O water + Cs2O ⟶ CsOH cesium hydroxide

Balance the chemical equation algebraically: H_2O + Cs2O ⟶ CsOH Add stoichiometric coefficients, c_i, to the reactants and products: c_1 H_2O + c_2 Cs2O ⟶ c_3 CsOH Set the number of atoms in the reactants equal to the number of atoms in the products for H, O and Cs: H: | 2 c_1 = c_3 O: | c_1 + c_2 = c_3 Cs: | 2 c_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 = 1 c_3 = 2 Substitute the coefficients into the chemical reaction to obtain the balanced equation: Answer: | | H_2O + Cs2O ⟶ 2 CsOH

+ Cs2O ⟶

water + Cs2O ⟶ cesium hydroxide

Construct the equilibrium constant, K, expression for: H_2O + Cs2O ⟶ CsOH 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: H_2O + Cs2O ⟶ 2 CsOH 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 | 1 | -1 Cs2O | 1 | -1 CsOH | 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 | 1 | -1 | ([H2O])^(-1) Cs2O | 1 | -1 | ([Cs2O])^(-1) CsOH | 2 | 2 | ([CsHO])^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])^(-1) ([Cs2O])^(-1) ([CsHO])^2 = ([CsHO])^2/([H2O] [Cs2O])

Construct the rate of reaction expression for: H_2O + Cs2O ⟶ CsOH 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: H_2O + Cs2O ⟶ 2 CsOH 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 | 1 | -1 Cs2O | 1 | -1 CsOH | 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 | 1 | -1 | -(Δ[H2O])/(Δt) Cs2O | 1 | -1 | -(Δ[Cs2O])/(Δt) CsOH | 2 | 2 | 1/2 (Δ[CsHO])/(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[H2O])/(Δt) = -(Δ[Cs2O])/(Δt) = 1/2 (Δ[CsHO])/(Δt) (assuming constant volume and no accumulation of intermediates or side products)

| water | Cs2O | cesium hydroxide formula | H_2O | Cs2O | CsOH Hill formula | H_2O | Cs2O | CsHO name | water | | cesium hydroxide IUPAC name | water | | cesium;hydroxide

| water | Cs2O | cesium hydroxide molar mass | 18.015 g/mol | 281.81 g/mol | 149.912 g/mol phase | liquid (at STP) | | solid (at STP) melting point | 0 °C | | 338.85 °C boiling point | 99.9839 °C | | density | 1 g/cm^3 | | 1.72 g/cm^3 surface tension | 0.0728 N/m | | dynamic viscosity | 8.9×10^-4 Pa s (at 25 °C) | | odor | odorless | |