Input interpretation
oxygen + red phosphorus ⟶ phosphorus pentoxide
Balanced equation
Balance the chemical equation algebraically: + ⟶ Add stoichiometric coefficients, c_i, to the reactants and products: c_1 + c_2 ⟶ c_3 Set the number of atoms in the reactants equal to the number of atoms in the products for O and P: O: | 2 c_1 = 10 c_3 P: | c_2 = 4 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_3 = 1 and solve the system of equations for the remaining coefficients: c_1 = 5 c_2 = 4 c_3 = 1 Substitute the coefficients into the chemical reaction to obtain the balanced equation: Answer: | | 5 + 4 ⟶
Structures
+ ⟶
Names
oxygen + red phosphorus ⟶ phosphorus pentoxide
Reaction thermodynamics
Enthalpy
| oxygen | red phosphorus | phosphorus pentoxide molecular enthalpy | 0 kJ/mol | -17.6 kJ/mol | -2984 kJ/mol total enthalpy | 0 kJ/mol | -70.4 kJ/mol | -2984 kJ/mol | H_initial = -70.4 kJ/mol | | H_final = -2984 kJ/mol ΔH_rxn^0 | -2984 kJ/mol - -70.4 kJ/mol = -2914 kJ/mol (exothermic) | |
Entropy
| oxygen | red phosphorus | phosphorus pentoxide molecular entropy | 205 J/(mol K) | 22.8 J/(mol K) | 229 J/(mol K) total entropy | 1025 J/(mol K) | 91.2 J/(mol K) | 229 J/(mol K) | S_initial = 1116 J/(mol K) | | S_final = 229 J/(mol K) ΔS_rxn^0 | 229 J/(mol K) - 1116 J/(mol K) = -887.2 J/(mol K) (exoentropic) | |
Chemical names and formulas
| oxygen | red phosphorus | phosphorus pentoxide Hill formula | O_2 | P | O_10P_4 name | oxygen | red phosphorus | phosphorus pentoxide IUPAC name | molecular oxygen | phosphorus |
Substance properties
| oxygen | red phosphorus | phosphorus pentoxide molar mass | 31.998 g/mol | 30.973761998 g/mol | 283.89 g/mol phase | gas (at STP) | solid (at STP) | solid (at STP) melting point | -218 °C | 579.2 °C | 340 °C boiling point | -183 °C | | density | 0.001429 g/cm^3 (at 0 °C) | 2.16 g/cm^3 | 2.3 g/cm^3 solubility in water | | insoluble | surface tension | 0.01347 N/m | | dynamic viscosity | 2.055×10^-5 Pa s (at 25 °C) | 7.6×10^-4 Pa s (at 20.2 °C) | odor | odorless | |
Units
