Which Represents an Enthalpy Change at 25 °C and 1

question 27

Multiple Choice

Which represents an enthalpy change at 25 °C and 1 atm that is equal to ΔH^o_f for H₂O(l) ?

• A) O₂(g) + 2H₂(g) → 2H₂O(l)
• B) ½O₂(g) + H (g) → H₂O(g)
• C) H₂(g) + ½O₂(g) → H₂O(l)
• D) 2H₂O(l) → O₂(g) + 2H₂(g)
• E) H₂O(l) → ½O₂(g) + H₂(g)

---

Definitions:

Equivalent Samples

Groups in a study or experiment that are made as similar as possible to ensure that results are due to the variable being tested rather than pre-existing differences among participants.

Cross-sectional

A research design that analyzes data from a population, or a representative subset, at a specific point in time.

Longitudinal

Relating to, involving, or measuring changes over time, especially in regards to the study or analysis of development or progression.

Longitudinal Design

A research strategy where subjects are followed and observed over a period of time to detect any changes in them.