# What is the enthalpy of CH4?

## What is the enthalpy of CH4?

The standard enthalpy of formation of CH4(g), CO2(g) and H2O(g) are -76.2, -394.8 and -241.6 kJ/mol respectively.

**What is the standard entropy of H2?**

131.0

Standard Entropy

Table 20.2.1: Standard Entropy Values at 25oC | |
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Substance | So(J/K⋅mol) |

H2(g) | 131.0 |

O2(g) | 205.0 |

H2O(l) | 69.9 |

**What is the standard entropy of a compound?**

The standard entropy (S°) is the absolute entropy of a pure material at 25°C (298 K) and 1 atm pressure. At any temperature over 0°K, the conventional entropies of all substances, whether elements or compounds, are always positive.

### Is formation of CH4 exothermic?

The heat of formation of methane is exothermic. When a C-H bond in methane is dissociated homolytically (BDE), the total energy expended is for the formation of a methyl radical and a hydrogen atom.

**What is the enthalpy for CH4 2O2 –> CO2 2H2O?**

The enthalpy change for the reaction CH4 + 2O2 -> CO2 + 2H2O at 298 K is -809 KJ/mol.

**Which substance has a standard entropy of zero?**

At absolute zero (0 K), the entropy of a pure, perfect crystal is zero. The entropy of a substance can be obtained by measuring the heat required to raise the temperature a given amount, using a reversible process.

## What is standard state entropy?

Standard molar entropy is defined as the entropy or degree of randomness of one mole of a sample under standard state conditions. Usual units of standard molar entropy are joules per mole Kelvin (J/mol·K).

**What is the molar entropy of ch4?**

−74.6 kJ/mol. Standard molar entropy, Sogas. 186.3 J/(mol K) Enthalpy of combustion ΔcHo.

**What is the standard entropy of N2?**

The Standard Entropies Of N2 (g), H2 (g) And NH3 (g) Are 191.5, 130.5, 192.6 JK–1 mol–1.

### Is the standard entropy of an element in its standard state is 0?

Because of this definition, the standard entropy of formation of an element in its standard state is zero.

**What is the standard heat of formation of methane CH4 g as calculated from the data above?**

Hence the enthalpy of formation of methane is −75kJ.

**What is the enthalpy of formation for C 2h2 → CH4?**

C + 2H2 ==> CH4 after cancelling the H2O’s and the O2’s on each side. Then add up the corresponding ∆H values which would be -393 kJ + (-572 kJ) + 890 kJ = -75 kJ This is the answer.

## What is the entropy of co2?

51.11 cal./deg. per mole

The entropy of carbon dioxide gas has been calculated from the calorimetric data and the third law of thermodynamics to be 51.11 cal./deg. per mole at 298.1°K.

**Is the standard entropy of any compound is greater than 0?**

Statement-2 : Standard entropy of all elements is greater than zero. Statement-3 : Entropy of all elements and compounds decreases with decrease of temperature and becomes zero at absolute zero temperature.

**Why are standard entropy values positive?**

Like standard enthalpy of formation values, standard entropies are tabulated for a wide range of substances. However, unlike enthalpy of formation values, all standard entropy values are positive, because the absolute zero for entropy is the most ordered possible state.

### What is the entropy of CO2?

**What is the standard entropy of so2?**

Entropy of gas at standard conditions (298.15 K, 1 bar.)

S°gas,1 bar (J/mol*K) | 248.223 ± 0.050 |

Method | Review |

Reference | Cox, Wagman, et al., 1984 |

Comment | |
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CODATA Review value |