Description : With rise of boiling point of a water, what will be the latent heat of steam?
Last Answer : Decreases
Description : Burns caused by steam are much severe than those caused by boiling water because – (1) Steam pierces through the pores of body quickly (2) Steam has latent heat (3) Steam is gas and engulfs the body quickly (4) Temperature of steam is higher
Last Answer : (2) Steam has latent heat Explanation: When water changes into steam, it absorbs latent heat, and when steam condenses to form water, it gives out an equal amount of latent heat. Bums caused ... boiling water, simply because steam contains more heat (in the form of latent heat) than boiling water.
Description : Burns caused by steam are much severe than those caused by boiling water because (1) Steam pierces through the pores of body quickly (2) Steam has latent heat (3) Steam is gas and engulfs the body quickly (4) Temperature of steam is higher
Last Answer : Steam has latent heat
Description : Vegetables are cooked in lesser time by adding a pinch of salt while cooking because (1) boiling point of water increases (2) latent heat of vaporization of water decreases (3) latent heat of vaporization of water increases (4) boiling point of water decreases
Last Answer : (1) boiling point of water increases Explanation: Adding salt raises the boiling point of water, which allows food to cook at higher temperature. The higher the temperature, the higher the rate of heat transfer between the food and water, thus it cooks more quickly.
Description : Water is not suitable as a calorimetric substance because it – (1) has high specific heat (2) is a good conductor (3) has high boiling point (4) low latent heat of vaporization
Last Answer : (1) has high specific heat Explanation: The specific heat of water is higher than all other common substances. Hence, water is used for heating purposes (as in hot water bottles) and for cooling ... the liquids, mercury has the lowest specific heat due to which it is used as a thermometric liquid.
Last Answer : boiling point of water increases
Description : Water is not suitable as a calorimetric substance because it : (1) has high specific heat (2) is a good conductor (3) has high boiling point (4) low latent heat of vapourization
Last Answer : has high specific heat
Description : Choose the correct statement (a) A refrigerant should have low latent heat (b) If operating temperature of system is low, then refrigerant with low boiling point should be used (c) Pre-cooling and sub-cooling bf refrigerant are same (d) Superheat and sensible heat of a. refrigerant are same
Last Answer : Ans: b
Description : Which of the following is not a desirable property of a refrigerant (a) highmisibility with oil (b) low boiling point (c) good electrical conductor (d) large latent heat
Last Answer : Ans: c
Description : It is desired to concentrate a 20% salt solution (20 kg of salt in 100 kg of solution) to a 30% salt solution in an evaporator. Consider a feed of 300 kg/min at 30°C. The boiling point of the solution is 110°C, the latent heat of ... 3.06 10 5 (B) 6.12 10 5 (C) 7.24 10 5 (D) 9.08 10
Last Answer : (A) 3.06 × 10
Description : Gibbs free energy per mole for a pure substance is equal to the (A) Latent heat of vaporisation (B) Chemical potential (C) Molal boiling point (D) Heat capacity
Last Answer : (B) Chemical potential
Description : Entrainer used in Azeotropic distillation should (A) Form a low boiling azeotrope with one of the constituents of the mixture (B) Form a new azeotrope of low relative volatility with one of the ... (C) Have high latent heat of vaporisation (D) Have high viscosity to provide high tray efficiency
Last Answer : (A) Form a low boiling azeotrope with one of the constituents of the mixture
Description : Steam at 100°C causes more severe burns than water at 100° C because – (1) steam has no specific heat capacity (2) steam has latent heat of vaporization (3) water has no specific heat capacity (4) water has latent heat of fusion
Last Answer : (2) steam has latent heat of vaporization Explanation: It is because steam releases its latent heat as it condenses, which is substantial. The heat of vaporization of steam is over 2000 J per gram. And when it releases that it's then 100 degree water, the same as boiling water.
Description : Latent heat absorbed by 1 lb of water at 212°F, when it is changed to steam at 212°F, may be around __________ BTU. (A) 180 (B) 970 (C) 3.97 (D) None of these
Last Answer : (A) 180
Description : n a chemical factory where dyes are made, wet cake at 30 OC consisting of 60% moisture is put in a dryer to obtain an output having only 5% moisture, at atmospheric pressure. In each batch about 120 ... dryer and the dryer efficiency is 80%. Latent heat of steam at 4 kg/cm2 is 520 kcal/kg.
Last Answer : Given that Qty of material dried per batch - 120 Kgs Moisture at inlet - 60% a. The quantity of moisture removed per batch. Water quantity in a wet batch - 120 x 0.6 = 72 Kgs. Quantity of bone dry ... - 48/0.95 = 50.5 Kgs. Equivalent water in a dry batch - 50.5 - 48 = 2.5 Kgs.
Description : Describe any two sources of air leak in surface condenser. Also describe effect of air leak on latent heat of steam and cooling water requirements.
Last Answer : ✓ The main sources of air leakage found in condenser are given below: 1) There is leakage of air from atmosphere at the joint of the parts which are internally under a pressure less ... hence evaporation enthalpy of steam increases therefore more amount of cooling water required in the condenser.
Description : Steam at 1000C causes more severe burns than water at 100° C because (1) steam has no specific heat capacity (2) steam has latent heat of vaporisation (3) water has no specific heat capacity (4) water has latent heat of fusion
Last Answer : steam has latent heat of vaporisation
Description : Latent heat of dry steam at atmospheric pressure is 539 Kcal/kg; which __________ with increase in the pressure of steam. (A) Decreases (B) Increases (C) Remain same (D) May increase or decrease
Last Answer : (A) Decreases
Description : The critical pressure at which the latent heat of vaporisation of steam becomes zero is __________ Kg/cm2. (A) 273.15 (B) 225.65 (C) 100.03 (D) 373.15
Last Answer : (B) 225.65
Description : A __________ is a type of heat exchange system where water is heated to its' boiling point via combustion of a fuel blown through a tube submerged in water. a. Condensate loop b. Hyperbolic cooling tower c. Steam boiler d. All of above
Last Answer : c. Steam boiler
Description : When the mixture to be distilled has a very high boiling point and the product material is heat sensitive, the separation technique to be used is __________ distillation. (A) Continuous (B) Steam (C) Azeotropic (D) None of these
Last Answer : (B) Steam
Description : . A dilute aqueous solution is to be concentrated in an evaporator system. High pressure steam is available. Multiple effect evaporator system is employed, because (A) Total heat transfer area of ... in a single effect is much lower than that in any effect in a multi-effect system
Last Answer : (B) Total amount of vapor produced per Kg of feed steam in a multiple effect system is much higher than in a single effect
Description : Pick out the wrong statement: (A) The capacity of an evaporator is reduced by the boiling point elevation (B) Corrosive liquid is normally passed through the tubes in a ... recompression evaporator (D) Heat sensitive materials should be concentrated in high pressure evaporators
Last Answer : (D) Heat sensitive materials should be concentrated in high pressure evaporators
Description : Pick out the wrong statement. (A) Economy of a multiple effect evaporator is not influenced by the boiling point elevation (B) Two identical cubes of iron and copper will have the same heat ... in the field of refrigeration (D) Finned tube heat exchangers are suitable for heating air by steam
Last Answer : (B) Two identical cubes of iron and copper will have the same heat content under the same conditions of temperature
Description : _________ nuclear reactor does not require a heat exchanger tosupply steam to power turbine. (A) Molten sodium cooled (B) Helium cooled (C) Boiling water (D) Pressurised water
Last Answer : (C) Boiling water
Description : The generated heat is transferred to water to make ______ the process of boiling. • Steam • Boiler • Both • None
Last Answer : • Steam
Description : During the first 10 minutes after injection of phage DNA, no phage can be recovered by disrupting the infected bacterium. This is termed as A- eclipse period B- rise period C- latent period D- burst size
Last Answer : eclipse period
Description : Which of the following situations can be approximated to a steady state heat transfer system? (A) A red hot steel slab (having outside surface temperature as 1300°C) exposed to the atmospheric air at ... flowing at the rate of 6 Kg/minute through a copper pipe exposed to atmospheric air at 35°C
Last Answer : (B) 10 kg of dry saturated steam at 8 kgf/cm2 flowing through a short length of stainless steel pipe exposed to atmospheric air at 35°C
Description : Why is it easier to cook in a pressure cooker? (a) High pressure creates turbulence (b) More steam is formed inside the cooker (c) Boiling point of water is raised (d) Boiling point of water is lowered
Last Answer : Ans:(c)
Description : steam distillation, the (A) Temperature is 100°C(B) Temperature is more than 100° C (C) Product must be immiscible with water (D) Temperature is higher than the boiling point of either component
Last Answer : (C) Product must be immiscible with water
Description : Pressure Cooker cooks faster because (1) boiling point decreases with rise of pressure (2) it cooks the food at low pressure (3) higher temperature is attained for cooking (4) the material of the cooker is a good conductor
Last Answer : (3) higher temperature is attained for cooking Explanation: In pressure cooker boiling point of water increases due to high pressure.
Description : Boiling point elevation of a solution of NaOH (A) Increases rapidly with temperature rise (B) Is almost independent of temperature (C) Is almost independent of pressure (D) Both (B) and (C)
Last Answer : (D) Both (B) and (C)
Description : Boiling point elevation of an ideal solution (A) Increases rapidly with temperature rise (B) Decreases rapidly with temperature rise (C) In independent of pressure (D) Both (B) and (C)
Last Answer : (A) Increases rapidly with temperature rise
Description : Pick out the wrong statement. (A) The value of hydrostatic head increases with increase in vacuum in the effect in a multiple effect evaporator system (B) Entering velocity of the liquid in ... a multiple effect evaporation system, the number of effects is limited by the total boiling point rise
Last Answer : (C) Duhring's plot is used for calculating the concentration of solution
Last Answer : higher temperature is attained for cooking
Description : When the solvent dissolves very little of solute, then (A) Solvent of low latent heat of vaporisation should be used (B) Solvent of low freezing point should be used (C) Large quantity of solvent is required to extract the solute (D) Very small quantity of solvent is required
Last Answer : (C) Large quantity of solvent is required to extract the solute
Description : ick out the undesirable property for a good refrigerant. (A) High thermal conductivity (B) Low freezing point (C) Large latent heat of vaporisation (D) High viscosity
Last Answer : (D) High viscosity
Description : Dew point temperature always gives an indication of the __________ of the moist air. (A) Dryness (B) Moisture content (C) Coolness (D) Latent heat
Last Answer : (B) Moisture content
Description : The heat absorbed by a unit mass of a material at its holding point in order to convert the material into a gas at the same temperature. a. Latent Heat of Sublimation b. Latent Heat of Vaporization c. Latent Heat of Fusion d. Latent Heat Of Condensation
Last Answer : Latent Heat of Vaporization
Description : A liquid with high boiling point decomposes on simple distillation but it can be steam distilled for its purification .Explain how is it possible?
Last Answer : In steam distillation boiling occurs when vapour pressure of organic compound & steam becomes equal to atmospheric pressure. As vapour pressure of water is higher than the organic liquid. ... organic liquid vaporizes at a temperature below its boiling point in steam distillation without decomposing.
Description : Explain ,why an organic liquid vapourises at a temperature below its boiling point in steam distillation?
Last Answer : Because for boiling to occur vapour pressure of organic compound & steam should be equal to atmospheric pressure. As vapour pressure of water is higher than organic liquid. Therefore, organic liquid vaporizes at a temperature below its boiling point in steam distillation .
Description : Nitrobenzene (boiling point = 210.6°C) is steam distilled at 1 atm pressure. Nitrobenzene will distil off __________ °C. (A) At < 100 (B) At > 210.6 (C) Between 100 and 210 (D) None of these
Last Answer : (A) At < 100
Description : Components, having widely different boiling point in a binary mixture, can be separated using __________ distillation. (A) Molecular (B) Extractive (C) Steam (D) Simple
Last Answer : (D) Simple
Description : Which petroleum refinery product has the lowest boiling point? -Do You Know?
Last Answer : answer:
Description : When air passes through silica gel, A. it absorbs water vapour molecules B. latent heat of condensation is released C.dbt of air increases D. all of the mentioned
Last Answer : ANSWER : D
Description : Heat stored in water vapour is – (1) specific heat (2) latent heat (3) absolute heat (4) relative heat
Last Answer : (2) latent heat Explanation: Latent heat is the heat released or absorbed by a body or a thermodynamic system during a process that occurs without a change in temperature. A typical example is a ... the boiling of water. So water vapor which is the end product of evaporated water has latent heat.
Description : Only small amount of evaporation of water produces large cooling effects because of its (A) Large latent heat (B) Low viscosity (C) Small latent heat (D) None of these
Last Answer : (A) Large latent heat
Description : For the air water system under ambient conditions, the adiabatic saturation temperature and the wet bulb temperature are nearly equal, because (A) Water has a high latent heat of evaporation (B) Lewis number is close to unity (C) They are always equal under all circumstances
Last Answer : (A) Water has a high latent heat of evaporation
Description : In a cooling tower, water becomes cool by (A) Loosing sensible heat (B) Heat transfer to surroundings (C) Vaporisation due to heat loss to air (D) Loosing latent heat
Last Answer : (A) Loosing sensible heat