IND 310 Gases and Vapors Homework 5 1. Which statement is true? a) Normal gases
ID: 235549 • Letter: I
Question
IND 310
Gases and Vapors
Homework 5
1. Which statement is true?
a) Normal gases are organic.
b) The solid or liquid state of a vapor substance exists in normal temperature and pressure.
c) Oxygen and formaldehyde are two examples of vapor.
d) The liquid and gaseous states of a substance have the same density.
2. Gas and vapor characteristics are usually given in normal temperature and pressure state (NTP) where ….
a) Temperature (T) = 32 deg F and pressure (p) = 1 atm.
b) T and p depend on the geographical location.
c) There is no specific pressure value, however the temperature is in room temperature.
d) 1 mole of any gas occupies 24.45 liter at NTP.
3. Which statement is not true regarding the vapor pressure?
a) Vapor pressure is independent of temperature.
b) At vapor pressure, vapor state is in equilibrium with solid or liquid state.
c) The chemical volatility is dependent on the vapor pressure.
d) None of the above.
4. Technicians A and B work in an LPG (liquefied petroleum gas) filling station. They mostly deal with butane and propane with the vapor pressure of 2.2 atm and 10.1 atm, respectively. Technician A says that since we fill tanks with the same volume, the potential hazard would be the same, and technician B says that butane is more potentially hazardous. You, as an industrial hygienist is to judge between the two, which technician is right?
a) Technician A.
b) Technician B.
c) Both A and B.
d) None of them.
5. Which combination of the health effect is not correct?
a) Nitrogen dioxide and anesthetics.
b) Xylene and nephrotoxins.
c) Phosgene and pulmonary toxins.
d) Benzene and hematopoietic toxins.
6. The temperature and pressure for gas laws must be in absolute form, in constant pressure if a tank contains 2 liter of propane in 20 deg C, what would be its volume when it is heated up to 40 deg C?
a) 4 liter.
b) 2.13 liter.
c) 2 liter.
d) Depends on the pressure.
7. Air is compressed from 1 atm to 6 atm, resulting to a temperature increase in the amount of 40 deg C from initial temperature of 25 deg C and volume of 20 liter. How much volume would it occupy after compression?
a) 3.50 liter.
b) 3.78 liter.
c) 5.33 liter.
d) 8.67 liter.
8. What are common expressions of concentration?
a) Mass over volume.
b) Parts of contaminants per million parts of air.
c) Contaminant density over the air density in NTP.
d) Both ‘a’ and ‘b’.
9. What is the ppm equivalent concentration of 100 mg/cubic meters benzene with the molecular weight of 78 mg/mmol ….
a) 31.35 ppm.
b) 100 ppm.
c) 15.7 ppm.
d) 24.45 ppm.
10. Is there a relationship between vapor pressure and saturation concentration in a storage tank?
a) No the two are two independent quantities.
b) Is a function of the ratio of the vapor pressure to the atmospheric pressure.
c) It depends on the hydrostatic pressure at the bottom of the tank.
d) None of the above.
Explanation / Answer
1.B. SInce vapour is the gaseous form of a substance that can coexist as solid or liquid at normal temperature and pressure so it is true
2.d. At NTP conditions are 25 degree celsius temperature and 760 mm Hg atmospheric pressure, 1 mole of any gas occupies 24.45 litres
3. a. Vapour pressure is dependent on temperature because higher the temperature, higher will be the vapour pressure.
4. D.The substance having higher vapour pressure are highly volatile and thus more potenitally hazardous even if their volumes are kept same. So here the propane having high vapour pressure of 10.2 atm wrt vapour pressure of butane which is 2.2 atm. So none of the technician is correct here because propane is more potentially hazardous than butane.
5. a. Nitrogen dioxide is associated with pulmonary toxins
6a. 4L
Acc to Charles law
V1/T1=V2/T2
V1=2L
T1=20 degree celsius
T2=40 degree celsius
V2=??
2/20=V2/40
V2=4L
So, volume of propane after it is heated to 40 degree celsius would be 4L
7. c.5.33 L
Combining Charles and boyle's law:
P1=1 atm
P2=6 atm
T2=40 degree celsius
T1=25 degree celsius
V1=20 L
V2=??
P1*V1/T1=P2*V2/T2
1*20/25=6*V2/40
1*20*40/25*6=V2
800/150=V2
V2=5.33 L
So, volume after compression would be 5.33 L
8. d.Common expression of concentration are ppm and mg/m3 which implies mass/volume. So here option d which implies that both a and b are correct.
9. a. 31.5 ppm
To convert: mg/m3 into ppm
100*24.45/78
=31.35 ppm
10. b. There is a relationship between vapour pressure and saturation concentration in the storage tank
Headspace saturation concentration=Vapour pressure contaminant(mm Hg) * 10exp6 / 760 mm Hg
So here it is the function of vapour pressure to the atmospheric pressure