Exams & Certification

Air having an approximate molar composition of 79% N2 and 21% O2 fills a 0.36-m3 vessel. The mass of mixture is 100 kg. The measured pressure and temperature are 101 bar and 180 K, respectively. Compare the measured pressure with the pressure predicted using (a) the ideal gas equation of state. (b) Kay’s rule. (c) […]

In which of the following cases would you feel weightless? while accelerating downward in an elevatorwhile falling from a roofwhile walking on the Moonwhile parachuting from an airplane The correct answer and explanation is : The correct answer is: while falling from a roof. Explanation: Weightlessness occurs when a person experiences free fall, meaning they

A hydrolysis reaction results in which two of the following? Water is split apart.Two molecules are split apart.Water is formed.Two molecules are combined. The correct answer and explanation is : The correct answer is: Two molecules are split apart. Explanation: A hydrolysis reaction is a chemical reaction in which water is used to break bonds

The explanation for refraction must involve a change in Warm air you A. speed.B. frequency.C. wavelength.D. all of these. The correct answer and explanation is : The correct answer is C. wavelength. Refraction refers to the bending of light (or any other wave) as it passes from one medium to another, where the speed of

A nozzle is supplied with steam having a specific enthalpy of 2780 k./kg at the rate of 9.1 kg/min. An outlet from the nozzle the velocity of the steam is 1070 m/s. Assuming that the inlet velocity of the steam is negligible and that the process is adiabatic, (a) The specific enthalpy of the steam

An air compressor requires 11.5 kW to deliver air at the rate of 2.3 kg/min. The compressor is cooled by water whose specific enthalpy rise during the process is not to exceed 35 kJ/kg. Assuming that the change in the kinetic energy of the air is negligible and that the heat energy loss to the

Enough of a monoprotic acid is dissolved in water to produce a 0.0192 M solution. The pH of the resulting solution is 2.53. Calculate the Ka for the acid. The correct answer and explanation is : To calculate the acid dissociation constant (Ka) for a monoprotic acid, we need to use the given pH value

Steam flows through a turbine stage at the rate of 4 500 kg/h. The steam velocities at inlet and outlet are 15 m/s and 180 m/s respectively. The rate of heat energy flow from the turbine casing to the surroundings is 23 kJ/kg of steam flowing. If specific enthalpy of the steam decreases by 420

Determine the shape factor, F12, for the rectangles shown. 6 m (2 0.5 mI 2 1 m (a) Perpendicular rectangles without a common edge (b) Parallel rectangles of unequal areas. The correct answer and explanation is : To determine the shape factor ( F_{12} ) for the rectangles in both scenarios (a) and (b), we

what is the name of the general reaction type that carboxylic acids, esters, and amides undergNucleophilic acyl additionElectrophilic acyl substitutionNucleophilic acyl substitutionElectrophilic acyl addition The correct answer and explanation is : The correct answer is Nucleophilic acyl substitution. Explanation: Nucleophilic acyl substitution is the general reaction type that occurs with carboxylic acids, esters, and amides.