Input interpretation
![H_2 hydrogen + Mg magnesium ⟶ MgH_2 magnesium hydride](../image_source/26ef7323f4e95e7bbbc0a667fa40580a.png)
H_2 hydrogen + Mg magnesium ⟶ MgH_2 magnesium hydride
Balanced equation
![Balance the chemical equation algebraically: H_2 + Mg ⟶ MgH_2 Add stoichiometric coefficients, c_i, to the reactants and products: c_1 H_2 + c_2 Mg ⟶ c_3 MgH_2 Set the number of atoms in the reactants equal to the number of atoms in the products for H and Mg: H: | 2 c_1 = 2 c_3 Mg: | 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 = 1 Substitute the coefficients into the chemical reaction to obtain the balanced equation: Answer: | | H_2 + Mg ⟶ MgH_2](../image_source/1546d7d31c2ea68eb570542fcaa8a015.png)
Balance the chemical equation algebraically: H_2 + Mg ⟶ MgH_2 Add stoichiometric coefficients, c_i, to the reactants and products: c_1 H_2 + c_2 Mg ⟶ c_3 MgH_2 Set the number of atoms in the reactants equal to the number of atoms in the products for H and Mg: H: | 2 c_1 = 2 c_3 Mg: | 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 = 1 Substitute the coefficients into the chemical reaction to obtain the balanced equation: Answer: | | H_2 + Mg ⟶ MgH_2
Structures
![+ ⟶](../image_source/8f9b0a257f10903226ba7767c02ccd2f.png)
+ ⟶
Names
![hydrogen + magnesium ⟶ magnesium hydride](../image_source/51dad09454c1e5452ea6c1011654235a.png)
hydrogen + magnesium ⟶ magnesium hydride
Reaction thermodynamics
Enthalpy
![| hydrogen | magnesium | magnesium hydride molecular enthalpy | 0 kJ/mol | 0 kJ/mol | -75.3 kJ/mol total enthalpy | 0 kJ/mol | 0 kJ/mol | -75.3 kJ/mol | H_initial = 0 kJ/mol | | H_final = -75.3 kJ/mol ΔH_rxn^0 | -75.3 kJ/mol - 0 kJ/mol = -75.3 kJ/mol (exothermic) | |](../image_source/dd24b3f0a50092700aa921ed2d122ca2.png)
| hydrogen | magnesium | magnesium hydride molecular enthalpy | 0 kJ/mol | 0 kJ/mol | -75.3 kJ/mol total enthalpy | 0 kJ/mol | 0 kJ/mol | -75.3 kJ/mol | H_initial = 0 kJ/mol | | H_final = -75.3 kJ/mol ΔH_rxn^0 | -75.3 kJ/mol - 0 kJ/mol = -75.3 kJ/mol (exothermic) | |
Equilibrium constant
![Construct the equilibrium constant, K, expression for: H_2 + Mg ⟶ MgH_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: H_2 + Mg ⟶ MgH_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 H_2 | 1 | -1 Mg | 1 | -1 MgH_2 | 1 | 1 Assemble the activity expressions accounting for the state of matter and ν_i: chemical species | c_i | ν_i | activity expression H_2 | 1 | -1 | ([H2])^(-1) Mg | 1 | -1 | ([Mg])^(-1) MgH_2 | 1 | 1 | [MgH2] 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 = ([H2])^(-1) ([Mg])^(-1) [MgH2] = ([MgH2])/([H2] [Mg])](../image_source/4b112a1a55d8b98fe542a707757a021a.png)
Construct the equilibrium constant, K, expression for: H_2 + Mg ⟶ MgH_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: H_2 + Mg ⟶ MgH_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 H_2 | 1 | -1 Mg | 1 | -1 MgH_2 | 1 | 1 Assemble the activity expressions accounting for the state of matter and ν_i: chemical species | c_i | ν_i | activity expression H_2 | 1 | -1 | ([H2])^(-1) Mg | 1 | -1 | ([Mg])^(-1) MgH_2 | 1 | 1 | [MgH2] 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 = ([H2])^(-1) ([Mg])^(-1) [MgH2] = ([MgH2])/([H2] [Mg])
Rate of reaction
![Construct the rate of reaction expression for: H_2 + Mg ⟶ MgH_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: H_2 + Mg ⟶ MgH_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 H_2 | 1 | -1 Mg | 1 | -1 MgH_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 H_2 | 1 | -1 | -(Δ[H2])/(Δt) Mg | 1 | -1 | -(Δ[Mg])/(Δt) MgH_2 | 1 | 1 | (Δ[MgH2])/(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[H2])/(Δt) = -(Δ[Mg])/(Δt) = (Δ[MgH2])/(Δt) (assuming constant volume and no accumulation of intermediates or side products)](../image_source/420b4079aa9f7589db25d226a9dd0b6e.png)
Construct the rate of reaction expression for: H_2 + Mg ⟶ MgH_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: H_2 + Mg ⟶ MgH_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 H_2 | 1 | -1 Mg | 1 | -1 MgH_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 H_2 | 1 | -1 | -(Δ[H2])/(Δt) Mg | 1 | -1 | -(Δ[Mg])/(Δt) MgH_2 | 1 | 1 | (Δ[MgH2])/(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[H2])/(Δt) = -(Δ[Mg])/(Δt) = (Δ[MgH2])/(Δt) (assuming constant volume and no accumulation of intermediates or side products)
Chemical names and formulas
![| hydrogen | magnesium | magnesium hydride formula | H_2 | Mg | MgH_2 Hill formula | H_2 | Mg | H_2Mg name | hydrogen | magnesium | magnesium hydride IUPAC name | molecular hydrogen | magnesium | magnesium hydride](../image_source/d07ddd4db4749cc022759325e6d04dec.png)
| hydrogen | magnesium | magnesium hydride formula | H_2 | Mg | MgH_2 Hill formula | H_2 | Mg | H_2Mg name | hydrogen | magnesium | magnesium hydride IUPAC name | molecular hydrogen | magnesium | magnesium hydride
Substance properties
![| hydrogen | magnesium | magnesium hydride molar mass | 2.016 g/mol | 24.305 g/mol | 26.321 g/mol phase | gas (at STP) | solid (at STP) | solid (at STP) melting point | -259.2 °C | 648 °C | 327 °C boiling point | -252.8 °C | 1090 °C | density | 8.99×10^-5 g/cm^3 (at 0 °C) | 1.738 g/cm^3 | 1.45 g/cm^3 solubility in water | | reacts | dynamic viscosity | 8.9×10^-6 Pa s (at 25 °C) | | odor | odorless | |](../image_source/e273831af0e2009a581dde89886c31ba.png)
| hydrogen | magnesium | magnesium hydride molar mass | 2.016 g/mol | 24.305 g/mol | 26.321 g/mol phase | gas (at STP) | solid (at STP) | solid (at STP) melting point | -259.2 °C | 648 °C | 327 °C boiling point | -252.8 °C | 1090 °C | density | 8.99×10^-5 g/cm^3 (at 0 °C) | 1.738 g/cm^3 | 1.45 g/cm^3 solubility in water | | reacts | dynamic viscosity | 8.9×10^-6 Pa s (at 25 °C) | | odor | odorless | |
Units