Engineering Sciences
GATE XE topic:ideal-gas-mixtures PYQs
Build your understanding with focused practice from past exam papers.
Questions 21–26 of 26. Imported answers require independent review unless marked reviewed.
Question 1
Open questionXE-EMCQ1 markNeeds review
One kg of an ideal gas (molecular weight = X) occupies a certain volume
at temperature
and pressure
. Four kg of another ideal gas (molecular weight = 2X) is added to the first gas keeping the volume
and temperature
same as before. The final pressure isYour answerChoose one option.
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Open questionXE-ENAT2 marksNeeds review
In a heating and humidification process, dry air (d.a) with relative humidity of 10% at ambient temperature of 10°C is mixed with superheated steam at temperature ‘T’. The resultant mixture is at 25°C with relative humidity of 50%. The total pressure before and after the process remains the same at 102 kPa. The saturated pressure of water vapor (
) at 10°C and 25°C are 1.2281 kPa, and 3.1698 kPa, respectively. The specific humidity in grams of water vapor per kg of dry air, can be calculated using
, where
and
are the partial pressures of water vapor and dry air respectively. The quantity of steam in grams (rounded off to 2 decimal places) added per kg of dry air is ______________.Log in to check the answer
You can attempt this question now. Sign in to view the answer key, explanations and discussion.Log in to check answerQuestion 1
Open questionXE-EMCQ1 markNeeds review
When a fixed mass of air-water vapour mixture is heated at constant pressure,
(A) both relative and specific humidity decrease.
(B) relative humidity decreases, but specific humidity remains unchanged.
(C) specific humidity decreases, but relative humidity remains unchanged.
(D) both relative and specific humidity increase.
Your answerChoose one option.
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You can attempt this question now. Sign in to view the answer key, explanations and discussion.Log in to check answerQuestion 17
Open questionXE-ENAT2 marksNeeds review
Moist air having 60% relative humidity, enters a steady-flow air-conditioning unit at 102 kPa and 30 °C. The volume flow rate of the moist air entering the unit is 0.1 m
/s. The moist air leaves the unit at 95 kPa and 15 °C with a relative humidity of 100%. Liquid condensate leaves the unit at 15 °C.
For water: at 15 °C,
kJ/kg,
kJ/kg,
kPa.
At 30 °C,
kJ/kg,
kJ/kg,
kPa.
For air, specific heat at constant pressure is 1.004 kJ/kg.K and the specific gas constant is 0.287 kJ/kg.K.
Neglecting heat leakage to the surrounding, the magnitude of heat extracted (in kW) from the air stream (up to 2 decimal places) is ________.Log in to check the answer
You can attempt this question now. Sign in to view the answer key, explanations and discussion.Log in to check answerQuestion 98
Open questionXE-ENAT2 marksNeeds review
Air contains by volume 79% N₂ (molecular weight = 28 kg/kmol) and 21% O₂ (molecular weight = 32 kg/kmol). A stream of air flows at 32°C, 1 bar, at a rate of 2 m³/s and is mixed with another stream of O₂ flowing at 0.4 kg/s. The molecular weight of the mixture (up to 2 decimal places) is _________.
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You can attempt this question now. Sign in to view the answer key, explanations and discussion.Log in to check answerQuestion 99
Open questionXE-ENAT2 marksNeeds review
Moist air enters a duct at a rate of 3 kg/s at 10°C, 80% relative humidity. The air is heated as it flows through the duct and exits at 30°C. No moisture is added or removed and the pressure of air in the duct is constant at 1 bar. The saturation vapor pressure (p_g) of H₂O at 10°C is 0.01228 bar. Specific enthalpy values of dry air at inlet and outlet of the duct are respectively 283.1 kJ/kg and 303.2 kJ/kg. The corresponding specific enthalpy values for water vapor are 2519.8 kJ/kg and 2556.3 kJ/kg. For steady state operation the amount of heat added to the moist air in kW (up to 2 decimal places) is _________.
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