Define empirical formula.
Hydrocarbon P is $85.7\%$ carbon by mass. Calculate the empirical formula of P. Show your working.
Molecules of P are straight-chain. Name the homologous series to which P belongs.
Q is a volatile hydrocarbon. $0.194\ \text{g}$ of gaseous Q occupies a volume of $71.5\ \text{cm}^3$ at $100^{\circ}\text{C}$ and $100\ \text{kPa}$. Use the ideal gas equation to calculate the $M_r$ of Q.
The mass spectrum of hydrocarbon R is recorded. The information for the two peaks with $m/e$ above $135$ is shown in Fig. 6.1. Use Fig. 6.1 to deduce the number of carbon atoms in a molecule of R. Show your working.
Use Fig. 6.1 and your answer to (c)(i) to work out the molecular formula of R.
Suggest the molecular formula of the fragment of R with $m/e = 57$.