Chem 219 Module 2- Reactions Test Questions Solved 100% Current Version 2025

Chem 219 Module 2- Reactions Test Questions Solved 100% Current Version 2025 Two types of reactions for Alkanes - Answers Combustion (oxidation) and Radical Halogenation (substitution) What does Combustion reaction produce? - Answers CO2 and H2O Is Combustion Endothermic or Exothermic? - Answers Exothermic What is exothermic? - Answers Heat (energy) is released The greater the number of carbons in an alkane, the _______ the amount of heat released in the combustion reaction - Answers GREATER Is the enthalpy (delta H) positive or negative in a combustion reaction? Why? - Answers Negative because heat is being released Why is a combustion reaction also called Oxidation? - Answers Carbon is combining with oxygen What occurs during a radical halogenation reaction? - Answers Halogen atoms replace hydrogen atoms on an alkane molecule Why is Radical Halogenation considered a Substitution reaction? - Answers Because halogen atoms substitute hydrogen atoms on the alkane What is the catalyst for Radical Halogenation? - Answers Heat or UV Halogen radicals in Radical Halogenation - Answers Species with a single unpaired electrons that attack the alkane substrate to pull off hydrogen atoms and substitute themselves in their place. Polyhalogenated products - Answers More than 1 H atom is replaced by a halogen Name the 5 "Addition" reactions in alkenes/alkynes - Answers Addition reaction Halogenation Hydration Addition of Acids to Alkenes Addition of Hydrogen to Alkenes Name the two oxidation reactions in alkenes/alkynes - Answers Oxidation with Potassium Permanganate Ozonolysis Why are addition reactions in alkenes thought of as combunations? - Answers Two different molecules join to form a single new compound What happens to the pi bond of the alkene in addition reactions? - Answers It is broken What happens to the sigma bond of the reagent in alkene addition reactions? - Answers It is broken What does the C atom in addition reactions gain? - Answers 2 new sigma bonds How does the geometry of the alkene in addition change? - Answers Goes from Trigonal planar to tetrahedral Is the product of alkene addition saturated or unsaturated? Why? - Answers Saturated because no new bonds can be made. Halogenation product for alkenes - Answers Alkyl Dihalide Why do alkenes readily add halogens? - Answers Because it is energetically favorable to do so (due to enthalpy) What happens during a Br Qualitative Test for Alkenes? - Answers Br is typically red/brown in color, but when it bonds with alkene, it is dibromoalkane and it is colorless. If you drop Br into a random substance, you will know it is alkene if the color changes to colorless. What happens in the Hydration of Alkenes? - Answers Alkenes add a water molecule across the double bond in the presence of an acid catalyst. What is the product of the hydration of an alkene? - Answers Alcohol (-OH) Why is an acid catalyst needed in the hydration of alkene? - Answers Neutral water molecules are not reactive enough to start a reaction on their own What does H and A stand for with H-A? - Answers H = acidic proton A = remainder of the acid