Thermochemical Equations Answers

Which statement is true if the Hrxn of a reaction is positive?

Sulfur reacts with oxygen to form sulfur dioxide (SO2(g), Hf = –296.8 kJ/mol) according to the equation below.What is the enthalpy change for the reaction? Use .

Hydrogen reacts with chlorine to form hydrogen chloride (HCl (g), Hf = –92.3 kJ/mol) according to the reaction below.Which statement is correct? Use .

Which statement about Hf is true?

Ammonia (NH3 (g), Hf = –45.9 kJ/mol ) reacts with oxygen to produce nitrogen and water (H2 O(g), Hf = –241.8 kJ/mol) according to the equation below.What is the enthalpy of the reaction? Use .

The enthalpy of formation for C6 H6 (I) is 49.0 kJ/mol. Consider the following reaction.Is the reaction endothermic or exothermic, and what is the enthalpy of reaction? Use .

Hydrogen ( H2 ) reacts with bromine ( Br2 ) to produce hydrogen bromide (HBr) gas as shown in the equation below.Standard Enthalpies of FormationSubstanceDHf (kJ/mol)Br2 (l)0.0Br2 (g)30.907HBr (g)–36.4HCl (g)–92.307HI (g)26.48H2 (g)0.0I2 (g)62.438Based on the equation and the information in the table, what is the enthalpy of the reaction?

Consider the reaction.Standard Enthalpies of FormationSubstanceDHf (kJ/mol)C2 H2 (g)226.73CaCO3 (s)–1206.92CaO (s)–635.09CO (g)–110.525CO2 (g)–393.509H 2 O (I)–285.8H 2 O (g)–241.818C (s), diamond1.895C (s), graphite0.0Based on the equation and the information in the table, what is the enthalpy of the reaction? Use .

Nitrogen reacts with hydrogen to form ammonia according to the equation below.Standard Enthalpies of FormationSubstanceDHf (kJ/mol)C2 H2 (g)–26.7NH3 (g)–46.19HBr (g)236.23HCl (g)–92.30HF (g)–268.6HI (g)25.9NaCl (s)–411.0Based on the equation and the information in the table, what is the enthalpy of the reaction?