Please anyone I need help with these questions. Please answer with explanation w
ID: 762329 • Letter: P
Question
Please anyone I need help with these questions. Please answer with explanation why and the picture of the structure, thanks. Using a chemical equation, explain why ethyl 4-aminobenzoate is insoluble in water at room temperature but soluble in dilute HCl. The structure of sodium benzoate is given. Upon addition of water, the salt readily dissolves. However, when HCl is added to this solution, a white precipitate forms. Using an equation, provide the identity of the white precipitate and explain its formation. The structure of the chloride salt of ethyl 4-aminobenzoate is shown below. Upon addition to water, the salt readily dissolves. However, when NaOH is added to this solution, a white precipitate forms. Using an equation, provide the identity of the white precipitate and explain its formation.Explanation / Answer
ChemistryPhysical ChemistryPhysical and Chemical ChangesChemical Change Top Chemical Change A change, in which the composition of a substance is altered, is called a chemical change. As a result, the original properties are changed and one or more new substances are formed. Iron is a greyish white metal which conducts electricity. It is attracted by a magnet and reacts with dilute acids to yield hydrogen. Sulfur is a non-metal, and is yellow in color. It dissolves in carbon disulphide. When powdered iron and sulfur are heated together, a completely new substance, iron sulphide is formed. The properties of iron sulphide are entirely different from those of iron and sulfur. It is black in color, does not get attracted by a magnet and does not allow electric current to pass through it. It reacts with dilute acids to from hydrogen sulphide gas. In short, the properties of neither iron nor sulfur are exhibited by iron sulphide. Change is an important part of our lives and we cannot ignore change. Personally, change is associated with growth, attitude and perception. In chemistry, change can be classified into two categories, namely physical change and chemical change. In a physical change, the chemical composition of the substance does not change, whereas, in a chemical change, the composition of the substance changes. Definition of chemical change "Chemical changes are changes in which new substances are formed, and theses changes cannot be reversed by reversing the conditions. Generally, energy is either absorbed or evolved during a chemical change." Chemical changes and rearrangement of atoms We have seen that matter is made up of atoms and a new substance is formed during a chemical change. Where does this new substance come from? According to the law of conservation of mass, matter can neither be created nor destroyed, so the total quantity of matter, i.e., the total mass, before and after a change, remains the same. So, the mass of the substances, taken together, before and after a chemical change, will also remain same. From this, it can be concluded that any new substance formed during a chemical change is due to the rearrangement of the atoms of the original substance. The number of atoms of each kind remains the same, before and after the chemical change. Let us take an example. When sodium hydroxide reacts with hydrogen chloride, then sodium chloride and water are formed. Here, the atoms of sodium, oxygen, chlorine and hydrogen, present in the molecules of NaOH and HCl, rearrange themselves. After rearrangement of these atoms, new molecules of NaCl and H2O are formed.