The variation of pressure with volume of the gas at different temperatures can be graphically represented as shown in figure.
On the basis of this graph answer the following questions.
(i) How will the volume of a gas change if its pressure is increased at constant temperature?
(ii) At a constant pressure, how will the volume of a gas change if the temperature is increased from 200 K to 400 K?
(i) The volume of a gas will decrease if the pressure on the gas is increased keeping the temperature constant.
(ii) The volume of a gas increases if the temperature is increased keeping the pressure constant.
2.9 g of a gas at 95 °C occupied the same volume as 0.184 g of hydrogen at 17 °C at the same pressure. What is the molar mass of the gas ?
Pressure versus volume graphs for a real gas and an ideal gas are shown in the figure.
Answer the following questions on the basis of this graph.
(i) Interpret the behaviour of real gas with respect to ideal gas at low pressure.
(ii) Interpret the behaviour of real gas with respect to ideal gas at high pressure.
(iii) Mark the pressure and volume by drawing a line at the point where real gas behaves as an ideal gas.
The pressure of a mixture of H2 and N2 in a container is 1200 torr. The partial pressure of nitrogen in the mixture is 300 torr. What is the ratio of H2 and N2 molecules in the mixture?
Give an expression for the van der Wools equation. Give the significance of the constants used in the equation. What are their units?
Assertion (A): Gases do not liquefy above their critical temperature, even on applying high pressure.
Reason (R): Above critical temperature, the molecular speed is high and intermolecular attractions cannot hold the molecules together because they escape because of high speed.
(a) Both A and R are true and R is the correct explanation of A.
(b) Both A and R are true but R is not the correct explanation of A.
(c) A is true but R is false.
(d) A is false but R is true.
Which of the following figures does not represent 1 mole of dioxygen gas at STP?
(a) 16 grams of gas
(b) 22.7 litres of gas
(c) 6.022 x 1023 dioxygen molecules
(d) 11.2 litres of gas
What will be the pressure of the gas mixture when 0.5 L of H2 at 0.8 bar and 2.0 L of dioxygen at 0.7 bar are introduced in all vessel at 27 °C?
Under which of the following two conditions applied together, a gas deviates most from the ideal behaviour?
(a) Low pressure (b) High pressure
(c) Low temperature (d) High temperature
At 25 °C and 760 mm ofHg pressure a gas occupies 600 mL volume. What will be its pressure at a height where temperature is 10 °C and volume of the gas is 640 mL?
Assertion (A): Three states of matter are the result of balance between intermolecular forces and thermal energy of the molecules. .
Reason (R): Intermolecular forces tend to keep the molecules together but thermal energy of molecules tends to keep them apart.
(a) Both A and R are true and R is the correct explanation of A.
(b) Both A and R are true but R is not the correct explanation of A.
(c) A is true but R is false.
(d) A is false but R is true.
Density of a gas is found to be 5.46 g/dm3 at 27 °C and at 2 bar pressure. What will be its density at STP?
Calculate the temperature of 4.0 moles of a gas occupying 5 dm3 at 3.32 bar (R = 0.083 bar dm3 K-1 mol-1)
A gas that follows Boyle's law, Charles' law and Avogadro's law is called an ideal gas. Under what conditions a real gas would behave ideally?
One of the assumptions of kinetic theory of gases states that "there is no force of attraction between the molecules of a gas."How far is this statement correct? Is it possible to liquefy an ideal gas? Explain.
One of the assumptions of kinetic theory of gases is that there is no force of attraction between the molecules of a gas.
State and explain the evidence that shows that the assumption is not applicable for real gases.
Compressibility factor, Z, of a gas is given as Z = PV/nRT
(i) What is the value of Z for an ideal gas?
(ii) For real gas what will be the effect on value of Z above Boyle's temperature?
The variation of vapour pressure of different liquids with temperature is shown in figure
(i) Calculate graphically boiling points of liquids A and B.
(ii) If we take liquid C in a closed vessel and heat it continuously, at what temperature will it boil?
(iii) At high altitude, atmospheric pressure is low (say 60 mm Hg). At what temperature liquid D boils?
(iv) Pressure cooker is used for cooking food at hill station. Explain in terms of vapour pressure why is it so?
Why does sharp glass edge become smooth on heating it up to its melting point in a flame? Explain which property of liquids is responsible for this phenomenon.
Explain the term ‘laminar flow'. Is the velocity of molecules same in all the layers in laminar flow? Explain your answer.
What will be the pressure exerted by a mixture of 3.2g of methane and 4.4g of carbon dioxide contained in a 9 dm3 flask at 27 °C?
A certain amount of a gas at 27 °C and 1 bar pressure occupies a volume of 25 m3. If the pressure is kept constant and the temperature is raised to 77 °C, what will be the volume of the gas?
A flask was heated from 27 °C to 227 °C at constant pressure. Calculate the volume of the flask if 0.1 dm3 of air measured at 227 °C was expelled from the flask.
(a) What do you mean by’Surface Tension'of a liquid?
(b) Explain the factors which can affect the surface tension of a liquid.
Two different gases ˜A' and ˜9' are filled in separate containers of equal capacity under the same conditions of temperature and pressure. On increasing the pressure slightly, the gas ˜A' liquefies but gas ˜B' does not liquefy even on applying high pressure until it is cooled. Explain this phenomenon.
Name the energy which arises due to motion of atoms or molecules in a body. How is this energy affected when the temperature is increased?
Assertion (A): At constant temperature, PV vs V plot for real gases is not a straight line.
Reason (R): At high pressure all gases have Z> 1 but at intermediate pressure most gases have Z < 1.
(a) Both A and R are true and R is the correct explanation of A.
(b) Both A and R are true but R is not the correct explanation of A.
(c) A is true but R is false.
(d) A is false but R is true.
Isotherms of carbon dioxide gas are shown in figure. Mark a path for changing . gas into liquid such that only one phase (i.e. either a gas or liquid) exists at any time during the change. Explain how the temperature, volume and pressure should be changed to carry out the change.
A vessel of 120 mL capacity contains a certain amount of gas at 35 °C and 1.2 bar pressure. The gas is transferred to another vessel of volume 180 mL at 35 °C. What would be its pressure?
A weather balloon has a volume of 175 dm3 when filled with hydrogen gas at a pressure of 1.0 bar. Calculate the volume of the balloon when it rises to a height where the atmospheric pressure is 0.8 bar. Assume that temperature is constant.
