Chemistry Questions

Sewage treatment generally involves three stages, called primary, secondary and tertiary treatment.

Primary treatment consists of temporarily holding the sewage in a quiescent basin where heavy solids can settle to the bottom while oil, grease and lighter solids float to the surface. This removes material that will either float or readily settle out by gravity. It includes the physical processes of screening, comminution, grit removal, and sedimentation.

Secondary treatment removes the soluble organic matter that escapes primary treatment. It also removes more of the suspended solids. Removal is usually accomplished by biological processes in which microbes consume the organic impurities as food, converting them into carbon dioxide, water, and energy for their own growth and reproduction.

Tertiary treatment includes removal of nutrients such as phosphorus and nitrogen and practically all suspended and organic matter from waste water.

Rayon is a versatile fiber. Rayon is chemically Cellulose. It is widely claimed to have the same comfort properties as natural fibers, although the drape and slipperiness of rayon textiles are often more like nylon. It can imitate the feel and texture of silk, wool, cotton and linen. The fibers are easily dyed in a wide range of colors.

A yellow element that stinks when burned is Sulphur.

To make steel, iron ore is first mined from the ground. It is then smelted in blast furnaces where the impurities are removed and carbon is added.

In simple, steel is iron alloyed with carbon, usually 0 - 2%.

The unit which is used to measure weighted average atomic mass is Atomic Mass Unit (amu).

The amu or gram/mole can also be used for this measure.