# Pressure and Temperature

## Trending Questions

**Q.**An empty LPG cylinder weighs 14.8 kg. When full, it weighs 29.0 kg and shows a pressure of 3.47 atm. In the course use at ambient temperature, the mass of the cylinder is reduced to 23.0 kg. The final pressure inside the cylinder is____

(Nearest Integer)

(Assume LPG to be an ideal gas)

**Q.**

Why is Mercury Used in Thermometers?

**Q.**

Why does the atmospheric pressure go on decreasing as we go higher up above the earths surface?

**Q.**If the mercury in the barometer is replaced by water, What will be the resulting height of the water column?

Given: Density of water = 1000 kgm3, Density of mercury = 13600 kgm3

- 10.3 m
- 11.2 m
- 9.8 m
- 0.76 m

**Q.**2 mol of ammonia occupied a volume of 5 L at 27 ∘C. Calculate the pressure if the gas obeyed van der Waals equation. (a=4.17 atm L2 mol−2, b=0.0371 L mol−1).

- 9.33 atm
- 4.66 atm
- 18.66 atm
- 12.32 atm

**Q.**Density of ice is less than that of water because of:

- absence of hydrogen bonding
- crystal modification of ice
- open porous structure of ice due to hydrogen bonding
- different physical states of these

**Q.**An ideal gas undergoes adiabatic expansion against external pressure. Which of the following are correct ?

- Internal energy of the gas remains unchanged
- Internal energy of the gas decrease
- Temperature of the system decreases
- ΔE+PΔV=0

**Q.**Which of the following statements is incorrect?

- It is not possible to compress a gas at a temperature below Tc.
- No condensation takes place above Tc
- The kinetic energy of the gas molecules is higher above Tc, and the attraction between them decreases.
- At a temperature below Tc, the molecules are slow enough for the attractive forces to act, and hence condensation occurs.

**Q.**Assume ideal gas behaviour for all the gases considered and neglect vibrational degrees of freedom. Separate equimolar samples of Ne, O2, CO2 and SO2 were subjected to a two process as mentioned. Initially all are at same state of temperature and pressure.

Step I→ All undergo reversible adiabatic expansion to attain same final volume, which is double the original volume thereby causing the decreases in their temperature.

Step II→ After step I all are given appropriate amount of heat isochorically to restore the original temperature.

Mark the correct option (s):

- Due to step I only, the decrease in temperature will be maximum for Ne
- During step II, heat given will be minimum for SO2
- There will be no change in internal energy for any of the gas after both the steps of process are completed
- The P−V graph of O2 and CO2 will be same

**Q.**A liquid confined inside as adiabatic container is suddenly taken from state 1 to state 2 by single stage process as shown, then choose the correct options(s)

- ΔH=2γP0V0γ−1
- ΔH=−P0V0
- w=−3P0V0
- ΔU=2P0V0γ−1

**Q.**A balloon having a volume of 4200 m3 is filled with a gas at 27∘C, and 1 bar pressure. It weighs 700 kg. If the density of air is 1.2 kg m−3, then the pay load of the balloon is:

- 4340 kg
- 5040 kg
- 5740 kg
- 3500 kg

**Q.**The ratio of height of a mercury column in a barometer at a place to the height of the liquid column at the same place are 1:4. Find the density of the liquid in g/cm3.

- 10.5 g/cm3
- 5.6 g/cm3
- 3.4 g/cm3
- 4.8 g/cm3

**Q.**In van der Waals equation at constant temperature 300 K, if a=1.4 atm L2 mol−2, V=100 mL, n=1 mol, then what is the pressure of the gas?

- 42 atm
- 210 atm
- 500 atm
- 106 atm

**Q.**

Calculate the pressure exerted by one mole of CO_{2} gas at 273 K, if the Van der Waals constant a = 3.592 dm^{6} atm molâ2. Assume that the volume occupied by CO_{2} molecules is negligible.

- 0.8422 atm
- 0.9922 atm
- 1.2 atm
- 1.1652 atm

**Q.**The height of water ρ=1000kg/m3 and oil ρ=720kg/m3 are 6 m and 5m inside an open barometer. What is the atmospheric pressure in kPa?

- 136.42 kPa
- 65.98 kPa
- 101.25 kPa
- 91.34 kPa

**Q.**The graph between log x/m v/s log P is straight line inclined at an angle 45degree with intercept 0.30. What will be rate of adsorption at pressure 0.4atm.

**Q.**In the figures given below, a doll is entrapped within a piston and cylinder containing gas. The initial and final conditions are shown as Fig. I and Fig. II respectively. The volume of doll is:

- 100 mL
- 100015 mL
- 1500017 mL
- 10003 mL

**Q.**Reversible expansion of an ideal gas under isotheramal and adiabatic conditions are as shown in the figure.

AB → Isothermal expansion

AC → Adiabatic expansion

Which of the following options is not correct?

- ΔSisothermal>ΔSadiabatic
- TA=TB
- Wisothermal>Wadiabatic
- TC>TA

**Q.**

The gas that does not show Joule Thomson effect is

**Q.**The given figure shows a mercury barometer. The atmospheric pressure is 101, 293 Pa. Find the pressure at points A, B and C.

(Density of mercury = 13.6 g/cc)

- PA=0
- PB = 66640 Pa
- PC = 101293 Pa
- PC = 82987 Pa

**Q.**

If one mole of a gas (mol.wt-40) occupies a volume of 20 litres, under the same conditions of temperature and pressure the volume occupied by 2 moles of gas (mol.wt=80) is

60 L

50 L

40 L

80 L

**Q.**Pressure of a gas is the result of:

- Molecular speed only
- Molecular speed and mass
- Molecular mass only
- Intermolecular forces

**Q.**Assertion :The lowest hypothetical or imaginary temperature at which gases are supposed to occupy zero volume is called absolute zero. Reason: Volume of the gas at −273.15∘C becomes zero i.e. gas does not exist at this temperature.

- Both Assertion and Reason are correct and Reason is the correct explanation for Assertion
- Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion
- Assertion is correct but Reason is incorrect
- Both Assertion and Reason are incorrect

**Q.**

2. (d) Define molecular space.

**Q.**Which of the following statement(s) are correct regarding gaseous state of matter?

- Complete order of molecules
- Complete diorder of molecules
- Random motion of molecules
- Fixed position of molecules

**Q.**what will be the pressure required at constant temperature, to compress a gas to 1/4th of its initial volume, if the initial pressure of a gas is 1 atm.

- 1 atm
- 2 atm
- 1 torr
- 4 atm

**Q.**

As height above sea level increases, atmospheric pressure

remains the same

increases

decreases

none of the above

**Q.**Which one of the following graph is not correct for an ideal gas?

- (I)
- (IV)
- (III)
- (II)

**Q.**A gas is allowed to expand in a well insulated container against a constant external pressure of 2 atm from an initial volume of 4.25 L to a final volume of 6.25 L. The change in internal energy (ΔU) of the gas will be:

- – 675 J
- + 675 J
- 405.2 J
- – 405.2 J

**Q.**

A student reads a barometer in the laboratory and finds the prevailing atmospheric pressure to be 720.0 mmHg. Which of the following is the correct option/s?

- 0.947 atm
- 95.99 kPa
- 9.599×103 Pa
- 720 torr