There are two overarching types of assessment in educational settings: informal and formal assessments. Both types are useful when used in appropriate situations. Informal assessments are those assessments that result from teachers' spontaneous day-to-day observations of how students behave and perform in class.
In the chemical industry it is used to heat reactants and in processes such as distillation, product drying, electrolysis, and treatment of waste. At present, the energy used still relies mainly on fossil fuels, but even so the use of these can be reduced in several ways (Table 2).
Inert gases are used generally to avoid unwanted chemical reactions degrading a sample. These undesirable chemical reactions are often oxidation and hydrolysis reactions with the oxygen and moisture in air . The term inert gas is context-dependent because several of the noble gases can be made to react under certain conditions.