Recrystallization method was achieved by the sample that contained benzoic acid, sodium chloride and p-nitroaniline. Heat the sample in a hot solvent. Reason that the acid and base and the salt didn’t react at this present is due by a weak base that won’t able to abstract a proton from the benzoic acid. Sodium chloride is the neutralization product of NaOH and HCl, which are a strong acid and base. Therefore, it won’t reform in acid or base so it concluded that no net reaction will take place overall.
How will you differentiate between physical and chemical equilibria? Ans. Physical equilibria do not involve changes to the chemical properties of the substances involved. For instance, equilibrium between water vapor and liquid water in a partly filled sealed container. It is a physical equilibrium since the water molecules have only changed from liquid to vapor.
The purpose of this experiment is to clarify these important distinctions. The physical properties of a substance are those properties that can be observed and measured without changing the composition of the substance. Physical properties include odor, color, density, solubility, boiling point, and melting point. Because they depend on there being no change in composition, physical properties can be used to describe and identify substances. A colorless, odorless liquid that freezes at 0°C is probably water, for example.
The melting point ranges of the impure and pure benzoic acid seemed reasonable. The difference between the literature melting point values of the pure Benzoic acid 21.5-22.5 is different than the one determined in the experiment. The recrystallization was experimentally showed as an inaccurate purification method. Introduction: Recrystallization is the purification technique in which a solid slowly forms, crystallize, from a liquid solution. It is based on the manipulation of the solubility at various temperatures.
Hydrate Lab The purpose of this lab is to analyze the percent water in a crystalline hydrate and to indentify the hydrate from a list of possible unknowns. The solid hydrate will be heated to remove the water, and the percent can be found by measuring the mass of the solid before and after heating. The hydrate will be indentified by comparing the percent water in the hydrate with the percent water calculated for the possible unknown. Before the lab there are pre-lab questions: 1. Describe the three general safety rules for working with a Bunsen burner.
What would you expect to happen if a solution of sodium benzoate was acidified? Write an equation. If a solution of sodium benzoate was acidified, Na in sodium benzoate solution will displaced by the H+ from the acid and thus producing benzoic acid. (C6H5)COO-Na+ + H2O/H+ → (C6H5)COOH + Na+ + OH- 3. Use your answers to Questions 1 and 2 to explain how a water-insoluble organic acid might be freed of non-acidic impurities.
Introduction The major component of eggshells is calcium carbonate (CaCO3). Calcium carbonate cannot be dissolved in water, but can dissolve in an acid using the reaction: 2HCl(aq)+CaCO3(s) Ca2+(aq)+CO2(g)+H2O+2HCl-(aq) This reaction is not used to titrate the CaCO3 because it is very slow when the reaction is close to the endpoint. Instead adding an excess of acid to dissolve all of the CaCO3 and then titrating the remaining H3O+ with NaOH solution can achieve the determination of the amount of acid, which has not reacted with the calcium carbonate. There are differences between amount of the acid (HCl) added and the amount left over after the reaction is equal to the amount used by the CaCO3. The reaction used to determine the leftover acid is: HCl (aq) + NaOH (aq) H2O + Na+ (aq) + Cl- (aq) Aim To measure the percent by mass of CaCO3 in an eggshell.
As for endothermic the reactions pulls in energy and makes it cold to touch. The other experiment measured the pH level in the reaction. The reaction consisted of sodium hydroxide and hydrochloric acid also to see at which point the reaction becomes neutralized. Neutralization is a reaction between an acid and a base forming a salt and water even tho you can’t see the salt due to the salt dissolving into the solution and the pH level of the reaction around level 7 and has a green sometimes yellow colour when the universal indicator is added. The neutralization gap shows how small the gap is to make the reaction neutral.
Purpose: The purpose of this lab is to investigate whether mass is gained or lost during a chemical reaction. Hypothesis: It will be found out that the mass is neither gained nor lost during a chemical reaction but transferred. Materials: * Safety goggles * Erlenmeyer flask * Balance * Graduated Cylinder * Beaker * Iron (III) chloride solution * Copper (II) sulphate solution * Sodium bicarbonate * Test tubes (small, and large) * Rubber Stopper * Tweezers * Paper towel * Scoopula * Sodium hydroxide solution * Hydrochloric acid Procedure: 1. 5ml of iron (III) chloride was measured and placed in the Erlenmeyer flask. 2.
Introduction A titration was carried out in this experiment to find the concentration of hydrochloric acid is an unknown solution. The aim of this experiment is to determine the number of moles of sodium hydroxide in hydrochloric acid and then to determine the number of moles of sodium hydroxide present in gastric juices. Titration, or volumetric analysis, is a common laboratory procedure for the analysis of substances and solutions. In a titration, the analyst determines the volume of a solution, called a titrant, that reacts exactly with a known weight or volume of another substance. This reaction is carried out by adding a solution of reactant hydrochloric acid from a burette to a solution of sodium hydroxide until just sufficient of hydrochloric acid has been added to react with all of the sodium hydroxide.