Energetics

What is the unit of enthalpy change (ΔH) in the International System of Units (SI)?

Which of the following processes is exothermic?

The enthalpy change of formation (ΔHf°) of an element in its standard state is always:

Calculate the enthalpy change (ΔH) when 2 moles of methane (CH₄) combust completely if the enthalpy of combustion of methane is -890 kJ/mol.

Which law states that energy can neither be created nor destroyed, only transformed?

Hess's Law is useful in calculating:

Given the reaction: C(s) + O₂(g) → CO₂(g), ΔH = -393.5 kJ/mol. What does the negative sign indicate?

Which of the following is a correct expression of Hess's Law?

In an endothermic reaction, the enthalpy change (ΔH) is:

Using bond enthalpies, calculate the approximate enthalpy change for the reaction: H₂ + Cl₂ → 2HCl. Given: Bond enthalpy H–H = 436 kJ/mol, Cl–Cl = 243 kJ/mol, H–Cl = 431 kJ/mol.