Specific Gravity is the ratio of the density of a liquid to the density of water, What is the Specific Gravity of a Gas?

Specific Gravity (Relative Density) SG also called relative density that is ratio of the density of a substance to that of a standard substance
What is Vapor Pressure

The vapor pressure of a liquid is the equilibrium pressure of a vapor above its liquid (or solid); that is, the pressure of the vapor resulting from evaporation of a liquid (or solid) above a sample of the liquid (or solid) in a closed container.
Is flow through a control valve turbulent or laminar?

Any process flow through piping and control valves is almost always considered as turbulent. The reason being the process has to go through so many twists and turns, expansion, reduction in piping, and elbows, valves, etc.
What is meant by Critical Pressure and Critical Temperature?

The critical pressure is the vapor pressure of a fluid at the critical temperature above which distinct liquid and gas phases do not exist. As the critical temperature is approached, the properties of the gas and liquid phases become the same, resulting in only one phase.
What is the trim in a control valve?

The internal parts of the valve body, valve stem, valve seat, packing set, valve plug, gasket, etc. are collectively referred to as valve trim. In other words, all wetted parts that can be disassembled and replaced in the valve body are part of the control valve trim.
What is the difference between a diffuser plate and a choke?

A choke valve is a type of control valve that has a restriction orifice that is used in oil and gas production wells to control the flow of good fluids being produced.
What is incipient cavitation?

Incipient cavitation represents the beginning stage of cavitation where light popping noises are heard. Constant cavitation is a steady rumbling sound associated with the start of possible valve damage.
What process data is required to size a control valve?

There are many process parameters that should be provided for the sizing of control valves. Here just examples of parts of the most important data for your reference.
What is the difference between rangeability and turndown?

Generally, the terms rangeability and turndown ratio are associated with control valve sizing and flow measuring devices.