(FUVEST 2011) - Question Medium of Chemistry

The search for alternative and more sustainable energy sources has led to the development of fuels composed of mixtures with ideal combustion characteristics. One of the challenges in this process is the improvement of the energy efficiency of internal combustion engines, which depends, in part, on the uniformity of the fuel mixture. Considering an internal combustion engine, where the efficiency of the fuel burning process is directly related to the homogeneity of the air-fuel mixture, a chemical engineer decides to investigate the behavior of different mixtures under pressure and temperature conditions similar to those found in the combustion chamber. For his analysis, he selects two mixtures: the first one is atmospheric air, mainly composed of nitrogen (78%), oxygen (21%), and other gases in lower concentrations, known to be a homogeneous mixture; the second one is a mixture of ethanol and water, in which ethanol and water form two distinct phases due to their differences in polarity and intermolecular interactions, considered a heterogeneous mixture. Based on the concepts of homogeneous and heterogeneous mixtures, which of the two mixtures investigated is more suitable to be used as fuel in an internal combustion engine, considering the goal of maximizing the energy efficiency of the burning process?

Nitro compounds are organic compounds that have one or more nitro groups (NO2) directly attached to a carbon atom of an alkyl or aryl group. They are commonly used as explosives due to their ability to rapidly decompose and release gases. Considering the IUPAC nomenclature rules for nitro compounds, answer: a) What is the correct nomenclature for the compound CH3CH2NO2? b) Write the molecular structure of 2,4-dinitrotoluene and identify the functional groups present in the molecule. c) According to the IUPAC rules, what is the name of the organic compound formed by substituting the three hydrogens of methane with three nitro groups?

Identify the organic function present in the ester of molecular formula C4H8O2 that is responsible for the aroma of a fruit. Consider that the ester has a carbon chain of 3 carbon atoms and a radical from a monocarboxylic acid of general formula CnH2nO2. Name the monocarboxylic acid and the alcohol used in the synthesis of this ester, following the IUPAC nomenclature rules for organic compounds. Justify the choice of the acid and the alcohol based on the structure and the desired aroma.