C2H2 = C4H4

C_2H_2 acetylene ⟶ C_4H_4 1-buten-3-yne

Balance the chemical equation algebraically: C_2H_2 ⟶ C_4H_4 Add stoichiometric coefficients, c_i, to the reactants and products: c_1 C_2H_2 ⟶ c_2 C_4H_4 Set the number of atoms in the reactants equal to the number of atoms in the products for C and H: C: | 2 c_1 = 4 c_2 H: | 2 c_1 = 4 c_2 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 = 2 c_2 = 1 Substitute the coefficients into the chemical reaction to obtain the balanced equation: Answer: | | 2 C_2H_2 ⟶ C_4H_4

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acetylene ⟶ 1-buten-3-yne

Construct the equilibrium constant, K, expression for: C_2H_2 ⟶ C_4H_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 C_2H_2 ⟶ C_4H_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 C_2H_2 | 2 | -2 C_4H_4 | 1 | 1 Assemble the activity expressions accounting for the state of matter and ν_i: chemical species | c_i | ν_i | activity expression C_2H_2 | 2 | -2 | ([C2H2])^(-2) C_4H_4 | 1 | 1 | [C4H4] 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 = ([C2H2])^(-2) [C4H4] = ([C4H4])/([C2H2])^2

Construct the rate of reaction expression for: C_2H_2 ⟶ C_4H_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 C_2H_2 ⟶ C_4H_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 C_2H_2 | 2 | -2 C_4H_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 C_2H_2 | 2 | -2 | -1/2 (Δ[C2H2])/(Δt) C_4H_4 | 1 | 1 | (Δ[C4H4])/(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[C2H2])/(Δt) = (Δ[C4H4])/(Δt) (assuming constant volume and no accumulation of intermediates or side products)

| acetylene | 1-buten-3-yne formula | C_2H_2 | C_4H_4 name | acetylene | 1-buten-3-yne IUPAC name | acetylene | but-1-en-3-yne

| acetylene | 1-buten-3-yne molar mass | 26.038 g/mol | 52.076 g/mol phase | gas (at STP) | gas (at STP) melting point | -81 °C | -93 °C boiling point | -75 °C | 5.1 °C density | 0.618 g/cm^3 (at -55 °C) | 0.7095 g/cm^3 (at 0 °C) surface tension | 0.01431 N/m |