OCR Chemistry Paper 2 exam questions with complete solutions

describe the structure of Benzene - correct answers: • a cyclic hydrocarbon with 6 carbon, and 6 hydrogen atoms. • the bond angle and shape around each carbon is 120' trigonal planar. • each C has 4 outer shell electrons; - 3 of these bond to 2 other carbon atoms, and 1 to a hydrogen atom. - these form a Sigma bond. - a fourth outer shell electron in the 2p orbital is left behind above and below the planes of the carbon atoms. • the electron in the p-orbital of a carbon atom overlaps with the electrons in a p-orbital of the carbon atoms on the other side. This results in a ring of electron density above and below the plane of carbon atoms. • this overlap produces a Pi bond. what is meant by the 'empirical formula'? - correct answers: • the simplest whole number ratio of atoms of each element present in a compound. what is meant by the 'molecular formula'? - correct answers: • the actual number of atoms of each element in a molecule.