I have no idea what these answers are, any help would be highly appreciated please! 1.) Why is hematite the most important ore of iron, although magnetite contains a higher percentage of iron? 2.) give two examples of minerals which are precipitated by the evaporation of seawater. 3.) what are some advantages and disadvantages of a synthetic gemstone to the buyer? Thank you sooo much! :D
Another place where you see the term 'commutator' is in quantum mechanics or in linear algebra. If A and B are operators, it is possible that AB and BA are different. The difference, AB-BA is called the commutator of A and B, and is written [A,B].
This Site Might Help You. RE: What is a commutator? What is a commutator? My friends have said something about it but I'm not really understanding it.
A commutator is an electrical switch that periodically reverses the current in an electric motor or electrical generator. Commutators enable motors to run on, and generators to produce, direct current instead of alternating current. More generally, commutators can be used to convert between direct and alternating current.
1) Yes, haematite is a more important iron ore mineral than magnetite even though it contains a lower percentage of iron. The reason for this that magnetite, being a spinel group mineral M2+(M3+)2O4, is very difficult to process in terms of ultimate extraction of the iron metal from the ore. Haematite is easy to process. 2) Two examples of minerals that are precipitated by the evaporation of seawater. a. Gypsum (CaSO4.2H2O) and b. Halite (NaCl) 3) The advantages / disadvantages of a synthetic gem to the buyer. The mining industry likes to convey that a synthetic gem isn't truly authentic. The mined gem contains natural impurities occasional small imperfections which are considered to make it the more genuine article. At the point of sale, a synthetic gem is normally cheaper to produce.
