GKFix MCQ Question

What is the value of R used in the calculation of ∆vapU?

• A. 0.0821 L atm K⁻¹ mol⁻¹
• B. 8.314 J K⁻¹ mol⁻¹
• C. 4.184 J cal⁻¹
• D. 1.987 cal K⁻¹ mol⁻¹