Questions

Cryogenic Engines find applications in Rocket technology. A cryogenic rocket engine is a rocket engine that uses a cryogenic fuel or oxidizer, that is, its fuel or oxidizer are gases liquefied and stored at very low temperatures. Notably, these engines were one of the main factors of NASA's success in reaching the Moon by the Saturn V rocket.

The systematic name for a chemical is the unique name given to it by the International Union of Pure Applied Chemistry (IUPAC). The IUPAC name can differ from a chemical compound's general name.

PbO is an ionic compound since it consists of a Lead as metal and Oxygen as nonmetal. The systematic name for PbO is Lead (II) oxide. Here we need to put the (II) since lead has more than one combining capacity.

The letter “c” with a line over it is a medical abbreviation often used by doctors, nurses, and other medical professionals. The symbol looks like this: c̄. The c is almost always lower-case.

This symbol actually has a very simple meaning. A c with a line over it just means “with”. This abbreviation is often used on patient charts and prescriptions, as well as information or notes written by medical professionals.