For the following set of pressure/volume data, calculate the new volume of the gas sample after the pressure change is made. Assume that the temperature and the amount of gas remain constant. a. 125 mL at 755 mm Hg; V =2mL at 780 mm Hg
b. 223 mL at 1.08 atm; V =2mL at 0.951 atm
c. 3.02 L at 103 kPa; V= 2Lat 121 kPa

a. 121 ml, b. 253 ml and c. 2.57 L.

Explanation:

The new volume can be calculated by using the Boyle's law equation:  

P1V1 = P2V2

In the equation, P1 and P2 are the initial and final pressures and V1 and V2 are the initial and final volumes for a real gas at constant temperature.  

a) Based on the given information, P1 = 755 mmHg, V1 = 125 ml, P2 = 780 mm Hg and V2 will be,  

V2 = P1V1/P2

V2 = 755 mmHg × 125 ml/780 mmHg

V2 = 121 ml

b) Based on the given information, P1 = 1.08 atm, V1 = 223 ml, P2 = 0.951 atm and V2 will be,  

V2 = P1V1/P2

V2 = 1.08 atm × 223 ml/0.951 atm

V2 = 253 ml

c) Based on the given information, P1 = 103 kPa, V1 = 3.02 L, P2 = 121 kPa and V2 will be,  

V2 = P1V1/P2

V2 = 103 kPa × 3.02 L/121kPa

V2 = 2.57 L

the enthalpy of formation of water is given as -285.8kj/mol, which states that the enthalpy of formation is negative.

negative enthalpy of formation indicates that the heat is released during the reaction process. the heat is released from reaction to the surroundings the enthalpy is expressed with a negative sign with the energy given out in the reaction process.

the formation of water takes place by giving out heat which is -285.8 kj/mol.