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#chemistry basics

3 public questions tagged with this topic.

Which of the following is NOT a state variable in thermodynamics?

**Specific heat capacity** c = Q/(m ΔT) (J/kg·K), molar C = Q/(n ΔT), heat required to raise temperature, Q = m c ΔT, for water c=4186 J/kg·K, latent heat L = Q/m for phase change at constant temperature, fusion L_f and vaporization L_v, Q = m L, e.g., ice melting L_f=3.34×10⁵ J/kg, water vaporization 2.26×10⁶ J/kg. State variables depend only on the current state of the system, not the path taken to reach it. Pressure, volume, and temperature are state variables. Heat ( Δ Q ) is not a state variable; it is a mode of energy transfer dependent on the process. Using first law

Ref: NCERT > Physics Book > Thermodynamics > Specific Heat Capacity and Latent Heat

What is the relationship between pH and pOH?

pH + pOH = 14 accurately defines or describes the concept asked in this question. Within Acid, Base, pH, precise definitions and terminology are essential for clear scientific communication. The other options (pH = 14 × pOH, pH + pOH = 7, and pH = 10⁻⁷ × pOH) either describe related but distinct concepts, use incorrect terminology, or confuse similar-sounding terms that have different scientific meanings. A thorough understanding of exact definitions helps distinguish between closely related biological concepts and is crucial for competitive examinations.

Ref: Lehninger Principles of Biochemistry, Nelson & Cox, 8th Ed., Ch. 2

What is the pH of a neutral solution at 25°C?

7 accurately defines or describes the concept asked in this question. Within Acid, Base, pH, precise definitions and terminology are essential for clear scientific communication. The other options (6, 8, and 9) either describe related but distinct concepts, use incorrect terminology, or confuse similar-sounding terms that have different scientific meanings. A thorough understanding of exact definitions helps distinguish between closely related biological concepts and is crucial for competitive examinations.

Ref: Lehninger Principles of Biochemistry, Nelson & Cox, 8th Ed., Ch. 2