Answer:
Compound: A substance that is made up of more than one type of atom bonded together.
Mixture: A combination of two or more elements or compounds which have not reacted to bond together; each part in the mixture retains its own properties.
Explanation:
The different substances in a mixture are not chemically combined, whereas the different elements in a compound are. The atoms do not combine in the mixture, but they combine when they form a compound.
I could fully answer the following question if it was in English
Density is defined as mass/volume (or m/v).
So,
(126.0 g)/(12.5 cm^3)= 10.08 g/cm^3
If your teacher requires correct significant figures, the answer is 10.1 g/cm^3.
If not, the first answer is fine.