S + KClO = SO2 + KCl

S mixed sulfur + KClO ⟶ SO_2 sulfur dioxide + KCl potassium chloride

Balance the chemical equation algebraically: S + KClO ⟶ SO_2 + KCl Add stoichiometric coefficients, c_i, to the reactants and products: c_1 S + c_2 KClO ⟶ c_3 SO_2 + c_4 KCl Set the number of atoms in the reactants equal to the number of atoms in the products for S, K, Cl and O: S: | c_1 = c_3 K: | c_2 = c_4 Cl: | c_2 = c_4 O: | c_2 = 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 = 2 c_3 = 1 c_4 = 2 Substitute the coefficients into the chemical reaction to obtain the balanced equation: Answer: | | S + 2 KClO ⟶ SO_2 + 2 KCl

+ KClO ⟶ +

mixed sulfur + KClO ⟶ sulfur dioxide + potassium chloride

Construct the equilibrium constant, K, expression for: S + KClO ⟶ SO_2 + KCl 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: S + 2 KClO ⟶ SO_2 + 2 KCl 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 S | 1 | -1 KClO | 2 | -2 SO_2 | 1 | 1 KCl | 2 | 2 Assemble the activity expressions accounting for the state of matter and ν_i: chemical species | c_i | ν_i | activity expression S | 1 | -1 | ([S])^(-1) KClO | 2 | -2 | ([KClO])^(-2) SO_2 | 1 | 1 | [SO2] KCl | 2 | 2 | ([KCl])^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 = ([S])^(-1) ([KClO])^(-2) [SO2] ([KCl])^2 = ([SO2] ([KCl])^2)/([S] ([KClO])^2)

Construct the rate of reaction expression for: S + KClO ⟶ SO_2 + KCl 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: S + 2 KClO ⟶ SO_2 + 2 KCl 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 S | 1 | -1 KClO | 2 | -2 SO_2 | 1 | 1 KCl | 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 S | 1 | -1 | -(Δ[S])/(Δt) KClO | 2 | -2 | -1/2 (Δ[KClO])/(Δt) SO_2 | 1 | 1 | (Δ[SO2])/(Δt) KCl | 2 | 2 | 1/2 (Δ[KCl])/(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[S])/(Δt) = -1/2 (Δ[KClO])/(Δt) = (Δ[SO2])/(Δt) = 1/2 (Δ[KCl])/(Δt) (assuming constant volume and no accumulation of intermediates or side products)

| mixed sulfur | KClO | sulfur dioxide | potassium chloride formula | S | KClO | SO_2 | KCl Hill formula | S | ClKO | O_2S | ClK name | mixed sulfur | | sulfur dioxide | potassium chloride IUPAC name | sulfur | | sulfur dioxide | potassium chloride

| mixed sulfur | KClO | sulfur dioxide | potassium chloride molar mass | 32.06 g/mol | 90.55 g/mol | 64.06 g/mol | 74.55 g/mol phase | solid (at STP) | | gas (at STP) | solid (at STP) melting point | 112.8 °C | | -73 °C | 770 °C boiling point | 444.7 °C | | -10 °C | 1420 °C density | 2.07 g/cm^3 | | 0.002619 g/cm^3 (at 25 °C) | 1.98 g/cm^3 solubility in water | | | | soluble surface tension | | | 0.02859 N/m | dynamic viscosity | | | 1.282×10^-5 Pa s (at 25 °C) | odor | | | | odorless