Any change in which the composition of material does not change that is it retains its identity but changes its state or form is known as a physical change.
The properties of metal to draw them into wires is known as ductility. When a copper is drawn into wire the only change that occurs is change in its shape and size no change will take place into its composition that is the wires are still possessing the properties of copper metal. Thus, a physical change takes place when copper is drawn into wire.
Since moles are just "some number of particles", and since one O2 molecule contains enough oxygen for two H2O molecules, you need 2.5 moles of O2 for 5 moles of H2O.
In this case, given the information about the aniline, whose molar mass is 93g/mol, one could assume the volume of the solution is just 200 mL (0.200 L) as no volume change is observed when mixing, therefore, the molarity results:
The two samples will have the same density because they are the same substance. The volume will have increased just enough to balance the greater mass. Key Concept- When substances have the same volumes but different masses, the substance having the greatest mass will be the most dense.
