1) Jeffrey Cox CHE111-DL01 Lab number 10 Stoichiometry of a Precipitation Reaction 2) Purpose/ Intro. In this lab we will be able to calculate the actual, theoretical, and percent yield of the product from a precipitation reaction. We will thusly learn the concepts of solubility and the formation of a precipitate. A precipitate reaction is a reaction in which soluble ions in separate solutions are mixed together to form an insoluble compound that settles out of the combined solution as a solid. The solid then is the insoluble compound, called a precipitate.
Computer Additivity of Heats of Reaction: Hess’s Law 18 (1) Solid sodium hydroxide dissolves in water to form an aqueous solution of ions. (2) Solid sodium hydroxide reacts with aqueous hydrochloric acid to form water and an aqueous solution of sodium chloride. NaOH(s) + H+(aq) ) + Cl–(aq) → H2O(l) + Na+(aq) + Cl–(aq) ∆H2 = ? OBJECTIVES • • • • In this experiment, you will Combine equations for two reactions to obtain the equation for a third reaction. Use a calorimeter to measure the temperature change in each of three reactions.
Heats of Solution and Reaction Name: Cindy Hernandez Purpose: The purpose of this experiment is to decided if the chemical reactions are exothermic and endothermic. By finding the differences between each temperature. Overview: For this lab, we had three different chemicals involved NH4Cl, H2SO4, and NaOH. What we did with these chemicals was that we added water, except NaOH we added HCl, was that we combined both mixtures to determine if there was a temperature change. The reason why we're determining if their was a chemical reaction is to identify if it is exothermic or endothermic.
Stoichiometry of a Precipitation Reaction Pre Lab Questions: (2Pts.) 1. What are the learning goals of this experiment? Predict the amount of product produced in a precipitation reaction, accurately measure the reactants and products of the reaction, determine the actual yield vs. theoretical yield, calculate the percent yield. 2.
There are a couple different ways to determine the percent composition of baking soda. The most common ways to find this percent composition are through titrations and thermal gravimetric analysis. When and if the NaHCO3 sample is found to be pure, these chemists must have a way to determine which salts are present. The best way to determine what the sample contains is by emission analysis. The first way to find the percent sample of baking soda is titration.
The salts will be dissolved in distilled water by small quantities until the reaction reaches When ionic compounds dissolve in water, they either absorb energy from or release energy to the surroundings. If a chemical reaction absorbs heat from the surroundings, it is an endothermic reaction. If a solution releases heat to its surroundings, it is an exothermic reaction. The enthalpy of dissolution is the enthalpy change associated with the dissolution of a substance in a solvent at a constant pressure. The change in enthalpy relies on the concentration of the salt solution, because different concentrations will produce different enthalpies.
ABSTRACT: The lab of “observations of chemical changes” was to observe the changes that occur in chemical reactions and attempt to interpret these changes. In these experiments it taught me how to interpret chemical reactions with acids and bases. Also, how one chemical can have many different reactions when combined with other chemicals and how to interpret each reaction as what it could mean. I discovered not only how to measure out a well-balanced chemical combination to receive a reaction but to know how to test for acids and bases using a few different methods. Other tests also included in this experiment were testing for Sodium Bicarbonate, and Starch.
Why is it important to determine these physical properties of a substance? The melting point of a solid is the point at which a solid becomes a liquid with standard atmospheric pressure. The boiling point of a liquid equals the external pressure. It is important to know these characteristics of a substance so that you can handle them in the correct manner. The boiling point and melting point can also be used to identify an unknown substance.
In this laboratory, we used physical and chemical properties to separate the components of a ternary (three substances) mixture. We also determine the percentage of each substance in the mixture. When distilled water is added to a mixture of NaCl (sodium chloride),
This technique prevents the product to contact other reactants, and leave the heating environment which might cause side reactions. The removal of the product also helps to shift the equilibrium position of the incomplete reaction to the right hand side, and prevents backwards reaction, resulting in an increased yield of products. This experiment also introduces the idea of azeotrope. An azeotrope is a mixture of two or more pure compounds in such a ratio that its composition cannot be changed by simple distillation. This is because when an azeotrope is boiled, the resulting vapour has the same ratio of constituents as the original mixture of liquids.