2 One major ore of copper is copper pyrite, CuFeS2.To extract copper from the ore, the ore is crushed, then undergoes froth
floatation and finally roasted in the air. The metal is then
purified by electrolysis.
(a) Explain why:-
The copper ore has to undergo froth-floatation
The copper ore is roasted in air
(b) Write a balanced chemical equation for the reaction that
occurs when copper is roasted.
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(b) which contains higher levels of vitamin b, oranges or spinach?

explanation:

you can eliminate a, c, and d because they are questions based on opinions.

chemical changes occur when a substance combines with another to form a new substance, called chemical synthesis or, alternatively, chemical decomposition into two or more different substances. these processes are called chemical reactions and, in general, are not reversible except by further chemical reactions. some reactions produce heat and are called exothermic reactions and others may require heat to enable the reaction to occur, which are called endothermic reactions. understanding chemical changes is a major part of the science of chemistry.