Molecular Physics | Thermodynamics Answers

What are the names and formulas of the conjugate bases of these acids: (a) HNO2, and (b) HCOOH (formic acid)?

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You are breathing at a rate of 20 breaths per minute in a warm, dry environment.

Each time you take a breath, you breathe in 0.5×10−3 kg of air at a temperature of 24°C and with a relative humidity of 20%. You breathe out the same mass of air but at a temperature of 36°C and a relative humidity of 100%.

How much water vapour do you exhale in one hour under these circumstances? (to 2 s.f and in g)

A furnace wall consists of 250 mm firebrick,125 mm insulating brick, and 250 mm building block.The inside wall is at a temperature of 600°C and the atmospheric temperature is 20°C.The heat transfer coefficient of the outside wall is 10 W/m2k, and the thermal conductivities of the fire brick, insulating brick, building brick are 1.4, 0.2, 0.7 W/m k respectively. Neglecting radiation, calculate the rate of the Heat Loss per unit wall surface area, and the temperature of the outside wall suface of the furnace.

[ANS:460 W/m2;60°C]

A 1.5 kg block of wood and a 2.5 kg block of steel are placed in thermal contact.

If the wood was at an initial temperature of 50°C and the steel was at an initial temperature of 15°C then what is the final equilibrium temperature of the wood and steel? (to 2 s.f and in °C)

[cwood = 2400 J kg−1 K−1, csteel = 490 J kg−1 K−1]

The 1.0-m-tall cylinder in FIGURE P14.61 contains air at a pressure of 1 atm. A very thin, frictionless piston of negligible mass is placed at the top of the cylinder, to prevent any air from escaping, then mercury is slowly poured into the cylinder until no more can be added without the cylinder overflowing. What is the height h of the column of compressed air?


Hint: Boyle’s law, which you learned in chemistry, says for a gas compressed at constant temperature, which we will assume to be the case.

A quantity of steam at 100 degree Celsius condenses to water at the same temperature by releasing 69000 joules of energy . Calculate the mass of the condensed steam if the specific latent heat of vaporization of water is 2300000 joules per kilogram

0.5kg of water at 10 degree Celsius is completely converted to ice at 0 degree Celsius by extracting 188000 joules of heat from it. If the specific heat capacity of water is 4200 joules per kilogram per Kelvin, calculate the specific latent heat of fusion of ice

Derive the constant A for a normalized one-dimensional Maxwellian distribution with variation from – infinity to + infinity.

F(u)= Ae-mu2/kT

The atmospheric pressure due to water is 1.3 x 106 Nm-2. What is the total pressure at the bottom of the ocean 10m deep. (Density of water = 1000kgm-3, g=10ms-2).

An engine is used to lift a 2700-kg truck to a height of 3.0m at constant speed. In the lifting . process, the engine received 4.18 x 105 J of heat from the fuel burned in its interior. What is the efficiency of the engine?