1. The molecular formula for elemental suphur is $S_g$. In a sample of 5.12g of sulphur:
(a) How many moles of sulphur are present,
(b) How many molecules and atoms are present?
2. If phosphorus is considered to contain $P_4$ molecules, then calculate the number of moles in 100 g of phosphorus?
3. Calculate:
(a) the gram molecular mass of chlorine if $308 c{m}^3$ of it at STP weighs 0.979 g,
(b) the volume of 4 g of $H_2$ at 4 atmosphere,
(c) the mass of oxygen in 2.2 litres of $C{O}_2$ at STP.
4. A student puts his signature with graphite pencil. If the mass of carbon in the signature is ${10}^{-12}g$, calculate the number of carbon atoms in the signature.