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The answer is equilibrium.
This is what is called dynamic equilibrium. It is the most common form of equilibrium in chemistry. It means that in average the system is not changing but if you look particle by particle they are changing. Giving that the rate at which the parciles pass from phase A to phase B is the same at which the particle pass from phase B to phase B, the system does not change, i.e. it is in equilibrium.
<span>The strong bonds give graphite high boiling and melting points, while the weak bonds make graphite soft and flexible.</span>
<span> the line-emission spectrum of an atom is caused by the energies released when electrons. releases energy of only certain values. </span>
Answer:
A. When a piece of copper is heated, it combines with oxygen to form copper oxide. The chemical reaction for the same is as follows:
2 Cu (s) + O2(g) => 2CuO
B. The mass of the piece of copper will remain same and there will be no change in its mass. However, its volume will increase, so its density will decrease.
C. This is so because heating copper in its elemental form is a physical change and there is no change in mass during a physical change. Hence, the mass of copper remain same.