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).
In a synthesis reaction, two or more simple substances combine to form a more complex substance. These reactions are in the general form: + Two or more reactants yielding one product is another way to identify a synthesis reaction. One example of a synthesis reaction is the combination of iron and sulfur to form iron(II) sulfide: + Another example is simple hydrogen gas combined with simple oxygen gas to produce a more complex substance, such as water. Decomposition