The little spheres represent water molecules. Molecules are in constant motion. The attractions water molecules have for each other keep them close together. They can move past each other, but their ...

Therefore, differences in density between metals are usually based on the size and mass of the atoms. Wood is made from a long molecule called cellulose. Cellulose is made from glucose molecules ...

\({\%~of~an~element} = \frac{mass~of~an~element~in~the~compound}{relative~formula~mass~M_r} \times 100\) There are six atoms of hydrogen in the compound, so the mass of hydrogen is 6 × 1 = 6.