Refrigerant-134a at 320 kpa and 40°c undergoes an isothermal process in a closed system until its quality is 45 percent. on a per-unit-mass basis, determine how much work and heat transfer are required.

What is a monomer? how do they form a ploymer from the view point of chemical bonding?

What is the maximum height from which a mass of 30 kg can fall on to a flange on the lower end of a vertical rod of length 1.0 m and diameter 20 mm, the upper end being rigidly fixed, if the stress in the rod is not to exceed 80 mpa? the tensile modulus of the rod is 200 gpa.

An inventor claims to have developed a reversed heat engine (ie. a heat pump) which is able to deliver 10 kj heat into the room at 20°c from outside ambient temperature of -10°c by consuming only 2 kj electricity in winter. this claim is a)-impossible b)-possible only if the heat pump is ideal c)-practically possible d)-unable to be assessed as it depends on the working fluid used in the heat pump.