Chemical Equilibrium Lab

6-3: This process is used by cells to manufacture _biochemical energy from nutrients into adenosine triphosphate (ATP), and then release waste products__

The main objective of this experiment is to differentiate between a physical change and a chemical change.

The mole is a convenient unit for analyzing chemical reactions. Avogadro’s number is equal to the mole. The mass of a mole of any compound or element is the mass in grams that corresponds to the molecular formula, also known as the atomic mass. In this experiment, you will observe the reaction of iron nails with a solution of copper (II) chloride and determine the number of moles involved in the reaction. You will determine the number of moles of copper produced in the reaction of iron and copper (II) chloride, determine the number of moles of iron used up in the reaction of iron and copper (II) chloride, determine the ratio of moles of iron to moles of copper, and determine the number of atoms and formula units involved in

Aim: The aim of the lab “Chemical Equilibrium” is to observe the effects of changes in concentrations of products and reactants on the position of the equilibrium of given chemical reactions.

The objective of the experiment is to apply Le Chatelier's Principle, which is a system that responds to an external stress and then adjusts itself in order to alleviate the stress when it is at equilibrium. A reactant is added, and the equilibrium is reestablished, resulting in more products and fewer reactants, and thus, the position of equilibrium is shifted to the right. When a product is added, the equilibrium position is shifted to the left because there are more reactants and fewer products.

The purpose of this lab was to determine the limiting reactant in a reaction between copper sulfate and iron. Using the reaction between copper sulfate and iron, the reaction was observed to see the reaction and transformation of matter. The copper sulfate was placed into a beaker, as the excess reactant, then iron filings added until the heated solution was completely reacted. This reaction created an excess of leftover. The law of conservation of mass can be observed in this reaction, and using the data found, the percent yield calculated.

Introduction: Chemical reactions are dependent upon two factors: temperature and concentrations of substance. We can monitor the rate at which a chemical decomposes or the rate at which a chemical substance appears. In this experiment we will be measuring the rate of decomposition of hydrogen dioxide with the following reaction:

Part 1: Obtain some 0.200M Fe(NO3)3 solution and some 0.00020M KSCN solution. Starting from the first solution, pour and mix 8.0mL of Fe(NO3)3 solution and 2.0mL of KSCN solution into a test tube, where as the second solution has 7.0mL of Fe(NO3)3 solution and 3.0mL of KSCN solution. Continue this process until 5 test tubes have been filled. Pour

Purpose: The purpose of this experiment is to observe a variety of chemical reactions and to identify patterns in the conversion of reactants into products.

In this experiment, two reactions were run to determine the molar absorptivity and the equilibrium constant of FeSCN2+. The main principles used in this lab are equilibrium, LeChatlier’s Principle, Beer’s Law and Spectrocopy. The first reaction was run to completion using LeChatier’s Principle and the second reaction was run to equilibrium. A spectrophotometer was used to measure absorbances. Using a graph of absorbance versus concentration of FeSCN2+ was used to determine that the molar absorptivity constant was 3670. Beer’s Law was used to determine that the average equilibrium constant was 33.1793.

Every chemical reaction eventually happens so that they approach a state of chemical equilibrium, where there is a dynamic balance between rate of formation of products and rate of formation of reactants. At this state, the concentrations of both products and reactants do not change. These concentrations give an equilibrium constant, k, which is found in this experiment with [FeSCN 2+ ]/[ Fe 3+ ] [ NCS]. Knowing that FeSCN 2+ is the only distinctively colored species in the solution, colorimetrically these equilibrium concentrations can be found, either by use of observation, part A, or by a spectrophotometer, part B. In this experiment, a standard solution is created to determine the concentration of FeSCN 2+ and in such a

The point of this experiment is to calculate an equilibrium constant for a chemical reaction by watching “Le Chatelier’s Principle” works in this experiment with iron (II) thiocynate. Le Chatelier's Principle is defined as, “A change in one of the variables that describe a system at equilibrium produces a shift in the position of the equilibrium that counteracts the effect of this change” (Purdue Web). Two things can happen within these shifts to relieve stress: The first one is the product concentration increases while the reactant concentration decreases, causing it to shift to the right. The second one is the product concentration decreases while reactant concentration increases, causing it to shift to the left (Purdue Web). In this experiment, iron (II) thiocyanate is the complex ion that is mixed with other solutions. Depending on which solution is mixed together with iron (II) thiocyanate that, will determine the color change trying to reach its equilibrium point. Equilibrium will be observed in the reaction of the iron ion and the thiocyanate ion. When color changes, it represents a “shift” in the chemical reaction. You can determine a shift in the solution by a color change. By observing this reaction at its equilibrium state, FeSCN 2+ can have either a shift to the right or to the left. FeSCN 2+

In this experiment, the changes in free energy (ΔG), enthalpy (ΔH), and entropy (ΔS) of the potassium nitrate’s (KNO3) dissolving reaction are determined by finding the equilibrium constant (Ksp). After this experiment is performed one should be able to have a better understanding of the thermodynamic properties and solubility constant (Ksp), and those properties relation to ∆G˚. Thermodynamics is the study of hat energy and other values of work, temperature, and energy regarding the process of a chemical reaction. A goal of this experiment is to be able to measure the solubility of KNO3 as a function of temperature, and analyze this function graphically. This graph is based off of solubility and temperature change, or more specifically the

3 because this is the maximum absorbance for the iron (III) ion. The Beer's Law Plot that was graphed came out to be linear with an equation of:

Chemical equilibrium is the study of change within a chemical reaction and how far it will go to reach a dynamic equilibrium (Burdge). Dynamic equilibrium is defined as the constant movement of species in a chemical reaction, gone to incompletion while the rates of production and consumption are equal (Kf = Kr ) (Burdge). It differs from static equilibrium in that species are constantly being consumed and produced, it is dynamic movement (Fox). The concentration of such species do not change, it remains constant (Fox). The rate at which species are being consumed and produced is known as the equilibrium constant (K) (Burdge). Due to the fact that the concentration