Mercury expands when it is heated. This process is called thermal expansion.
Answer:
The amount of molecules in CH4, also known about methane is simply 0.85 * 6.02210 * 10^23 This amounts to about 5.1 * 10^23
The answer is (3) metallic. Cobalt is a transition metal, so it can't be covalent bonds, which bond non-metals, therefore eliminating choice 1 and 2. Ionic bonds are between metals and non metals, but solid cobalt does not have a non metal, eliminating choice 4 as well. Metallic bonds are bonds between metals, therefore the answer is (3) metallic.
higher temp=faster motion
lower temp=slowed motion