1 is D - double-replacements do not make solid metals
2 is A - to have complete combustion the original compound must ONLY have C, H and O
3 is B - the elemental Mg replaces the H in the HCl
Answer: 45.038
Explanation: 2.016 H (2*1.008) + 15.999 O (1*15.999)
Answer:
Each carbon atom is covalently bonded to 4 other carbon atoms in diamond. A large amount of energy is required to split these atoms apart. This is because of the fact that covalent bonds are strong.
Selenium is a non metal, radon is a noble gas, silicon is a metalloid, and sulphur is a non metal. Hafnium is a transition metal.