In this worksheet, we will practice defining a vapor's relative humidity as the ratio of the partial pressure of the vapor to its equilibrium vapor pressure.

**Q1: **

On a warm day when the air temperature is , a metal can is slowly cooled by adding bits of ice to liquid water in it. Condensation first appears when the can reaches . What is the relative humidity of the air?

**Q4: **

Per mole, the atmosphere of a planet consists of nitrogen,
oxygen, and hydrogen. In modeling the
planet’s atmosphere, use a value of 28.0 g/mol for the molar mass of N_{2},
32.0 g/mol for the molar
mass of O_{2}, and 2.02 g/mol for the molar mass of H_{2}.

What is the mass of the nitrogen in 1.0 mol of this planet’s atmosphere?

The atmosphere of this planet is mixed with pentane in a ratio of by mass. Find the partial pressure of pentane in this mixture at an overall pressure of 2.50 atm. Use a value of 72.2 g/mol for the molar mass of pentane.

**Q5: **

What are the temperature and pressure of water at the triple point?

- A 0 K and 0.611 kPa
- B 373 K and 101 kPa
- C 273 K and kPa
- D 273 K and 0.611 kPa
- E 173 K and 611 kPa

**Q6: **

In a system, a water vapour mixture is at equilibrium at a temperature of 473 K. What is the pressure of the system?

- A 4.76 MPa
- B 3.25 MPa
- C 0.176 MPa
- D 1.52 MPa
- E 0.781 MPa

**Q7: **

A rigid vessel contains water vapour mixture in equilibrium at a pressure of 4.76 MPa. What is the temperature of the system?

- A 202℃
- B 150℃
- C 373℃
- D 473℃
- E 250℃

**Q8: **

A system contains water at a pressure of 4 MPa and a temperature of . What is the phase of this water?

- ALiquid-vapor mixture
- BVapor
- CSolid
- DLiquid
- ESolid-liquid mixture

**Q9: **

A system contains water at a pressure of 4 MPa and a temperature of . What is the phase of this water?

- ALiquid
- BLiquid-vapor mixture
- CSolid
- DVapor
- ESolid-liquid mixture

**Q10: **

A rigid vessel with a volume of 200 m^{3} contains a saturated liquid-vapour mixture
with a vapour quality of . The temperature of the vessel is maintained
at 393 K. What is the total mass of the
liquid-vapour mixture inside the vessel?

- A 179 kg
- B 219 kg
- C 359 kg
- D 299 kg
- E 199 kg