Maharashtra State Board
- Calculate the temperature of 5.0 mol of a gas occupying 5 dm3 at 3.32 bar. (R = 0.083 bar dm3 K-1 mol-1) Given: n = number of moles = 5.0 mol, V = volume = 5 dm³ P = pressure = 3.32 bar, R = 0.083 bar dm³ K⁻¹ mol⁻¹ To find: Temperature (T) Formu... 1
- Calculate the number of moles of hydrogen gas present in a 0.5 dm3 sample of hydrogen gas at a pressure Given: V = 0.5 dm³ = 0.5 × 10⁻³ m³, P = 101.325 kPa = 101.325 × 10³ Pa = 101.325 × 10³ Nm⁻² T = 27 °C = 27 + 273.15 K = 300.15 K, R = 8.314... 1
- What is an ideal gas? The gases which obey’ ideal gas equation over a complete range of temperature and pressure are called ideal gases. For an ideal gas, the rat... 1
- What are real gases? Gases, which do not obey ideal gas equation under all the conditions of temperature and pressure are called real gases. For real gases, the... 1
- Explain the reason for deviations of gases from ideal behaviour. A deviation from the ideal behaviour is observed at high pressure and low temperature. It is due to two reasons. The intermolecular attracti... 1
- Explain: Liquefaction of CO2 with the help of pressure vs volume isotherm. Answer: Andrews' P–V isotherms of CO₂ show that CO₂ can be liquefied by pressure only below its critical temperature, 30.98 °C; at this temp... 1
- Define: Critical temperature, critical volume and critical pressure. i. The temperature above which a substance cannot be liquified by increasing pressure is called its critical temperature (T_c). ii. The mola... 1
- Water has Tc = 647.1 K and Pc = 220.6 bar. What do these values imply about the state of water under ordinary conditions The T_c and P_c values of water are very high compared to the room temperature and common atmospheric pressure. As a result, water exists in... 1
- Gases possess characteristic critical temperature which depends upon the magnitude of intermolecular forces When cooling of ammonia and carbon dioxide gas is started from 500 K, then ammonia reaches its critical temperature first (i.e., 405.5 K.) a... 1
- CO2 has Tc = 38.98 °C and Pc = 73 atm. How many phases of CO2 coexist at i. 50 °C and 73 atm ii. 20 °C and 50 atm. i. 50 °C and 73 atm represent a condition for CO₂ above its T_c. Therefore, under this condition CO₂ exists only as single phase. ii. 20° C... 1
- In which of the following cases, water will have the highest and the lowest boiling point? Higher the pressure to which a liquid is exposed, higher will be its boiling point. The pressure to which water is exposed is maximum in the... 1
- Define: Liquid state Liquid state is the intermediate state between solid state and gaseous state. 2
- Give reason: Liquid possesses properties such as fluidity, definite volume and ability to take shape of the bottom Molecules of liquid are held together by moderately strong intermolecular forces and can move about within the boundary of the liquid. As a... 1
- Name some measurable properties of liquid. Density Boiling point Freezing point Vapour pressure Surface tension Viscosity. 1
- What are the factors affecting vapour pressure? Factors affecting vapour pressure: Nature of liquid: Liquids having relatively weak intermolecular forces possess high vapour pressure. Such... 1
- Explain how temperature affects surface tension. Surface tension is a temperature dependent property. When attractive forces are large, surface tension is large. Surface tension decreases a... 1
- Mention some applications of surface tension. Applications of surface tension: Cleaning action of soap and detergent is due to the lowering of interfacial tension between water and oily... 1
- Give reason: Liquid droplets acquire spherical shape. For a given volume of a liquid, spherical shape always imparts minimum surface area thereby reducing the surface tension. Hence, liquid drop... 2
- Define: Coefficient of viscosity Coefficient of viscosity is defined as the degree to which a fluid resists flow under an applied force, measured by the tangential frictiona... 1
- Describe various factors affecting viscosity of a liquid. Factors affecting viscosity of a liquid: i. Temperature: Viscosity is a temperature dependent property. Viscosity ∝ 1/ Temperature ii. Natur... 1
- Describe three daily life instances where viscosity plays an important role. Lubricating oils are viscous liquids. Gradation of lubricating oils is done on the basis of viscosity. A good quality lubricating oil does n... 1
- A balloon containing 0.6 mol of helium gas has a volume of 1.5 L. i. The volume of the balloon increases. ii. The volume of the balloon decreases. 2
- In an experiment conducted to study the diffusion of gases using same experimental conditions, following data i. Volume of gas A diffused = 50 cm³ Time required for diffusion = 7 minutes = 7 × 60 seconds Rate\ of\ diffusion\ of\ a\ gas =Volume\ of \... 1
- What makes the oil rise through the wick in an oil lamp? In an oil lamp, oil rises through the wick due to the capillary action. Such a capillary rise of oil is due to surface tension of oil. The w... 1