Academic Integrity: tutoring, explanations, and feedback — we don’t complete graded work or submit on a student’s behalf.

1. An ideal gas (which is is a hypothetical gas that conforms to the laws govern

ID: 891835 • Letter: 1

Question

1.

An ideal gas (which is is a hypothetical gas that conforms to the laws governing gas behavior) confined to a container with a massless piston at the top. (Figure 2)  A massless wire is attached to the piston. When an external pressure of 2.00 atm is applied to the wire, the gas compresses from 6.60 to 3.30 L . When the external pressure is increased to 2.50 atm, the gas further compresses from 3.30 to 2.64 L .

In a separate experiment with the same initial conditions, a pressure of 2.50 atm was applied to the ideal gas, decreasing its volume from 6.60 to 2.64 L in one step.

If the final temperature was the same for both processes, what is the difference between q for the two-step process and q for the one-step process in joules?

2. A volume of 110. mL of H2O is initially at room temperature (22.00 C). A chilled steel rod at 2.00 C is placed in the water. If the final temperature of the system is 21.50  C , what is the mass of the steel bar?

Use the following values:

specific heat of water = 4.18 J/(gC)

specific heat of steel = 0.452 J/(gC)

3. The specific heat of water is 4.18 J/(gC). Calculate the molar heat capacity of water.

Explanation / Answer

1. As you are asking about changes in volumes I assume q as work done within the system.

W=PDeltaV

Two steps process

a. W=202650Pa*(6.6E-03 - 3.3E-03)L= 668.745 J

2. Qwater=QSteel

mwaterCpwater(T2-T1)=msteelCpsteel(T2-T1)

Solving for msteel, msteel=26.08g Steel bar.

3. 4.18 J/(g*°C) * (18g /mol) = 75.24 J/(mol*°C)

b. W=50662.5Pa*(3.3E-03 - 2.64E-03)L= 33.43725J

total = 702.18225J

One step process

W= 253312.5Pa*(6.6E-03 - 2.64E-03)L= 1003.1175 J

2.