Pressure and Temperature

Q. An empty $LPG$ cylinder weighs $14.8kg$. When full, it weighs $29.0kg$ and shows a pressure of $3.47atm$. In the course use at ambient temperature, the mass of the cylinder is reduced to $23.0kg$. The final pressure inside the cylinder is____$atm$.
(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 = $1000kg{m}^3$, Density of mercury = $13600kg{m}^3$

1. $10.3m$
2. $11.2m$
3. $9.8m$
4. $0.76m$

Q. $2\text{mol}$ of ammonia occupied a volume of $5\text{L}$ at $27{}^{\circ }C$. Calculate the pressure if the gas obeyed van der Waals equation. $(a=4.17{\text{atm L}}^2{\text{mol}}^{-2},b=0.0371{\text{L mol}}^{-1})$.

1. $9.33\text{atm}$
2. $4.66\text{atm}$
3. $18.66\text{atm}$
4. $12.32\text{atm}$

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

1. absence of hydrogen bonding
2. crystal modification of ice
3. open porous structure of ice due to hydrogen bonding
4. different physical states of these

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

1. Internal energy of the gas remains unchanged
2. Internal energy of the gas decrease
3. Temperature of the system decreases
4. $\Delta E+P\Delta V=0$

Q. Which of the following statements is incorrect?

1. It is not possible to compress a gas at a temperature below $T_c$.
2. No condensation takes place above $T_c$
3. The kinetic energy of the gas molecules is higher above $T_c$, and the attraction between them decreases.
4. At a temperature below $T_c$, 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 $Ne,O_2,C{O}_2$ and $S{O}_2$ were subjected to a two process as mentioned. Initially all are at same state of temperature and pressure.
$\text{Step}I\to$ All undergo reversible adiabatic expansion to attain same final volume, which is double the original volume thereby causing the decreases in their temperature.
$\text{Step}II\to$ After step $I$ all are given appropriate amount of heat isochorically to restore the original temperature.
Mark the correct option (s):

1. Due to step $I$ only, the decrease in temperature will be maximum for $Ne$
2. During step $II$, heat given will be minimum for $S{O}_2$
3. There will be no change in internal energy for any of the gas after both the steps of process are completed
4. The $P-V$ graph of $O_2$ and $C{O}_2$ 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)

1. $\Delta H=\frac{2\gamma P_0{V}_0}{\gamma -1}$
2. $\Delta H=-P_0{V}_0$
3. $w=-3P_0{V}_0$
4. $\Delta U=\frac{2P_0{V}_0}{\gamma -1}$

Q. A balloon having a volume of $4200{\text{m}}^3$ is filled with a gas at ${27}^{\circ }\text{C},and1$ bar pressure. It weighs $700\text{kg}$. If the density of air is $1.2{\text{kg m}}^{-3}$, then the pay load of the balloon is:

1. $4340\text{kg}$
2. $5040\text{kg}$
3. $5740\text{kg}$
4. $3500\text{kg}$

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/$c{m}^3$.

1. 10.5 g/$c{m}^3$
2. 5.6 g/$c{m}^3$
3. 3.4 g/$c{m}^3$
4. 4.8 g/$c{m}^3$

Q. In van der Waals equation at constant temperature $300K$, if $a=1.4atm{L}^{2}mo{l}^{-2}$, $V=100mL$, $n=1mol$, then what is the pressure of the gas?

1. $42atm$
2. $210atm$
3. $500atm$
4. $106atm$

Q.

Calculate the pressure exerted by one mole of CO₂ gas at 273 K, if the Van der Waals constant a = 3.592 dm⁶ atm mol−2. Assume that the volume occupied by CO₂ molecules is negligible.

1. 0.8422 atm
2. 0.9922 atm
3. 1.2 atm
4. 1.1652 atm

Q. The height of water $\rho =1000kg/m^3$ and oil $\rho =720kg/m^3$ are 6 m and 5m inside an open barometer. What is the atmospheric pressure in kPa?

1. 136.42 kPa
2. 65.98 kPa
3. 101.25 kPa
4. 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:

1. $100\text{mL}$
2. $\frac{1000}{15}\text{mL}$
3. $\frac{15000}{17}\text{mL}$
4. $\frac{1000}{3}\text{mL}$

Q. Reversible expansion of an ideal gas under isotheramal and adiabatic conditions are as shown in the figure.
AB $\to$ Isothermal expansion
AC $\to$ Adiabatic expansion

Which of the following options is not correct?

1. $\Delta S_{isothermal}>\Delta S_{adiabatic}$
2. $T_A=T_B$
3. $W_{isothermal}>W_{adiabatic}$
4. $T_C>T_A$

Q.

The gas that does not show Joule Thomson effect is

1. 

2. 

3. 

4. 

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)

1. $P_A=0$
2. $P_B$ = 66640 Pa
3. $P_C$ = 101293 Pa
4. $P_C$ = 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

1. 60 L

2. 50 L

3. 40 L

4. 80 L

Q. Pressure of a gas is the result of:

1. Molecular speed only
2. Molecular speed and mass
3. Molecular mass only
4. 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 $-{273.15}^{\circ }C$ becomes zero i.e. gas does not exist at this temperature.

1. Both Assertion and Reason are correct and Reason is the correct explanation for Assertion
2. Both Assertion and Reason are correct but Reason is not the correct explanation for Assertion
3. Assertion is correct but Reason is incorrect
4. 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?

1. Complete order of molecules
2. Complete diorder of molecules
3. Random motion of molecules
4. Fixed position of molecules

Q. what will be the pressure required at constant temperature, to compress a gas to $1/4^{th}$ of its initial volume, if the initial pressure of a gas is $1\text{atm}$.

1. $1\text{atm}$
2. $2\text{atm}$
3. $1\text{torr}$
4. $4\text{atm}$

Q.

As height above sea level increases, atmospheric pressure

1. remains the same

2. increases

3. decreases

4. none of the above

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

1. (I)
2. (IV)
3. (III)
4. (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 $\left(\Delta U\right)$ of the gas will be:

1. – 675 J
2. + 675 J
3. 405.2 J
4. – 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?

1. 0.947 atm
2. 95.99 kPa
3. $9.599\times {10}^3$ Pa
4. 720 torr