Circle the items which can be considered as pure substances

Circle the item(s), which can be considered as pure substance(s) in Thermodynamics: (A) Drinking water (H_2O) with ice. (B) A mixture of liquid and gaseous nitrogen. (C) Gasoline and air in a fuel tank. (D) A mixture of drinking water and ethanol. (E) A flowing mixture of N_2 and CO_2 at a room temperature and atmospheric pressure. Please mark the region representing the superheated vapor: (A) Region A. (B) Region B. (C) Region C. (D) Region D. (E) None of above. Please circle the process (or processes) which can occur in a saturated liquid-vapor mixture (A) Melting. (B) Vaporization. (C) Condensation. (D) Sublimation (E) All of the above. Please circle the valid statement(s) about compressed liquid at temperature T and pressure P: (A)T P_T. (B) T > T_P. (C) v > v_(specific volume). (D) u h_(specific enthalpy).

Solution

The correct answers are

(1a) A and B

(drinking water with ice, a mixture of liquid and gaseous nitrogen )

(1b) Region D

(1c) A,B,C

(1d)A

(1e)B,C,E