Thermochemical Equations Instruction

Ammonia (NH3(g), Hf = -46.19 kJ/mol) reacts with hydrogen chloride (HCl(g), Hf = -92.30 kJ/mol) to form ammonium chloride (NH4Cl(s), Hf = -314.4 kJ/mol) according to this equation:NH3(g) + HCl(g) NH4Cl(s)What is Hrxn for this reaction?

-175.9

Completely reacting 150.0 g of a substance with oxygen releases 395.1 J of energy. How much energy would be released if 450.0 g of the substance completely reacted with oxygen?

1,185.3

How much energy must be added to 2 mol H2O(g) to cause it to decompose into H2 and O2?

483.64

What is the enthalpy of reaction for the decomposition of calcium carbonate?CaCO3(s) CaO(s) + CO2(g)

656.3 endothermic reaction

Which of these statements are true? Select all that apply. The Delta.Hf for Br2(I) is 0 kJ/mol. The Delta.Hf for He(I) is 0 kJ/mol. The Delta.Hf for Hg(I) is 0 kJ/mol. The Delta.Hf for Cl2(g) is 0 kJ/mol. The Delta.Hf for N2(I) is 0 kJ/mol.

A, C, D.

Using the information in the table to the right, calculate the enthalpy of combustion of each of the following substances: acetylene: kJ/mol ethanol: kJ/mol

Acetylene: -1,256 kJ/mol Ethanol: -1,277 kJ/mol

Is this reaction endothermic or exothermic?

Exothermc

Which substances have Hf = 0 kJ/mol by definition? Select all that apply.

O2(g) Br2(l) Fe(s) He(g)

The combustion of 0.25 mol of an unknown organic compound results in the release of 320 kJ of energy. Which of the compounds in the table could be the unknown compound?

ethanol