General Chemistry Labs II
- Page ID
- 211793
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\(\newcommand{\avec}{\mathbf a}\) \(\newcommand{\bvec}{\mathbf b}\) \(\newcommand{\cvec}{\mathbf c}\) \(\newcommand{\dvec}{\mathbf d}\) \(\newcommand{\dtil}{\widetilde{\mathbf d}}\) \(\newcommand{\evec}{\mathbf e}\) \(\newcommand{\fvec}{\mathbf f}\) \(\newcommand{\nvec}{\mathbf n}\) \(\newcommand{\pvec}{\mathbf p}\) \(\newcommand{\qvec}{\mathbf q}\) \(\newcommand{\svec}{\mathbf s}\) \(\newcommand{\tvec}{\mathbf t}\) \(\newcommand{\uvec}{\mathbf u}\) \(\newcommand{\vvec}{\mathbf v}\) \(\newcommand{\wvec}{\mathbf w}\) \(\newcommand{\xvec}{\mathbf x}\) \(\newcommand{\yvec}{\mathbf y}\) \(\newcommand{\zvec}{\mathbf z}\) \(\newcommand{\rvec}{\mathbf r}\) \(\newcommand{\mvec}{\mathbf m}\) \(\newcommand{\zerovec}{\mathbf 0}\) \(\newcommand{\onevec}{\mathbf 1}\) \(\newcommand{\real}{\mathbb R}\) \(\newcommand{\twovec}[2]{\left[\begin{array}{r}#1 \\ #2 \end{array}\right]}\) \(\newcommand{\ctwovec}[2]{\left[\begin{array}{c}#1 \\ #2 \end{array}\right]}\) \(\newcommand{\threevec}[3]{\left[\begin{array}{r}#1 \\ #2 \\ #3 \end{array}\right]}\) \(\newcommand{\cthreevec}[3]{\left[\begin{array}{c}#1 \\ #2 \\ #3 \end{array}\right]}\) \(\newcommand{\fourvec}[4]{\left[\begin{array}{r}#1 \\ #2 \\ #3 \\ #4 \end{array}\right]}\) \(\newcommand{\cfourvec}[4]{\left[\begin{array}{c}#1 \\ #2 \\ #3 \\ #4 \end{array}\right]}\) \(\newcommand{\fivevec}[5]{\left[\begin{array}{r}#1 \\ #2 \\ #3 \\ #4 \\ #5 \\ \end{array}\right]}\) \(\newcommand{\cfivevec}[5]{\left[\begin{array}{c}#1 \\ #2 \\ #3 \\ #4 \\ #5 \\ \end{array}\right]}\) \(\newcommand{\mattwo}[4]{\left[\begin{array}{rr}#1 \amp #2 \\ #3 \amp #4 \\ \end{array}\right]}\) \(\newcommand{\laspan}[1]{\text{Span}\{#1\}}\) \(\newcommand{\bcal}{\cal B}\) \(\newcommand{\ccal}{\cal C}\) \(\newcommand{\scal}{\cal S}\) \(\newcommand{\wcal}{\cal W}\) \(\newcommand{\ecal}{\cal E}\) \(\newcommand{\coords}[2]{\left\{#1\right\}_{#2}}\) \(\newcommand{\gray}[1]{\color{gray}{#1}}\) \(\newcommand{\lgray}[1]{\color{lightgray}{#1}}\) \(\newcommand{\rank}{\operatorname{rank}}\) \(\newcommand{\row}{\text{Row}}\) \(\newcommand{\col}{\text{Col}}\) \(\renewcommand{\row}{\text{Row}}\) \(\newcommand{\nul}{\text{Nul}}\) \(\newcommand{\var}{\text{Var}}\) \(\newcommand{\corr}{\text{corr}}\) \(\newcommand{\len}[1]{\left|#1\right|}\) \(\newcommand{\bbar}{\overline{\bvec}}\) \(\newcommand{\bhat}{\widehat{\bvec}}\) \(\newcommand{\bperp}{\bvec^\perp}\) \(\newcommand{\xhat}{\widehat{\xvec}}\) \(\newcommand{\vhat}{\widehat{\vvec}}\) \(\newcommand{\uhat}{\widehat{\uvec}}\) \(\newcommand{\what}{\widehat{\wvec}}\) \(\newcommand{\Sighat}{\widehat{\Sigma}}\) \(\newcommand{\lt}{<}\) \(\newcommand{\gt}{>}\) \(\newcommand{\amp}{&}\) \(\definecolor{fillinmathshade}{gray}{0.9}\)- 1.1: Introduction to Laboratory Techniques
- In this experiment, you will learn how to use a variety of chemistry laboratory equipment and instruments to make measurements. You will use an analytical balance and mass by difference to determine the masses of various samples. You will use a ruler to measure the dimensions and determine the volume and the density of a rectangular solid. You will also use burets to deliver a given amount of an unknown solution to determine its density.
- 1.2: Scientific Measurements. Precision and Accuracy
- The purpose of this activity is to get familiar with the approximate precision of the equipment in your laboratory. You will practice how to record measurements with an appropriate number of significant figures.
- 1.3: Density of the Salt Solution
- The goal of the experiment(s) we will be doing is to become directly involved in scientific inquiry. Gaining first-hand knowledge of the processes of scientific inquiry, problem solving, and critical thinking is of equal or greater importance than knowing the “correct” answers to problems.
- 1.4: Graphical Analysis with Logger Pro
- Vernier’s Logger Pro® is a graphical analysis software that will allow you to collect, graph and manipulate data. This lab will give you some practice using the program, especially since you will use it many times in your chemistry courses.
- 1.5: Graphical Analysis with Excel
- Excel is a computer spreadsheet program that scientists use to manipulate and graph data. This lab will ensure that you are able to use this program. In order to use Excel, you will need to collect mass and volume data. You will use this data to calculate density.
- 2.1: Nomenclature
- In this lab, you will learn the rules for naming compounds.
- 3.1: Determination of Avogadro's Number by Electrolysis
- It is determined experimentally by indirect means, in this case, by an electrolysis experiment. To get a very precise value of Avogadro’s number, we would need some expensive equipment. However, there are several ways that students can get a reasonably accurate value by inexpensive means.
- 3.2: Determination of Avogadro's Number Using a Monolayer
- The number of drops contained in one milliliter of oleic acid solution in petroleum ether will be determined. One drop of the oleic acid solution will be placed on a water surface covered with powdered cinnamon. As the oleic acid spreads on the surface of the water, the cinnamon powder will be pushed aside, making the size of the oleic acid film visible. The area of the film will be calculated.
- 3.3: Chemical Formula Determination
- The chemical formula of your unknown copper chloride hydrate will be in the general form CuxCly·zH2O. Your objective is to determine what the actual formula is (what are the integers x, y, and z?) You will be required to make careful mass measurements and to figure out what information will need to be recorded and what calculations will be performed.
- 4.1: Double Replacement or Metathesis Reactions
- Many chemical reactions occur in an aqueous environment (i.e., in a solution where ions and compounds are dissolved in water). When a reactant or product has the physical state “(aq)”, it means the substance is dissolved in water.
- 4.2: Properties of Solutions. Electrolytes and Nonelectrolytes
- In this experiment, you will discover some properties of strong electrolytes, weak electrolytes, and non-electrolytes by observing the behavior of these substances in aqueous solutions. You will determine these properties using a conductivity probe.
- 5.1: Limiting Reactant
- Stoichiometry is the quantitative study of reactants and products in chemical reactions. Thus, stoichiometric calculations involve using balanced chemical equations to relate amounts of reactants and products to each other using mole-to-mole ratios.
- 6.1: Beer's Law
- The primary objective of this experiment is to determine the concentration of a common food-dye, Allura Red, in Kool-Aid using Beer’s Law and a technique called spectrophotometry (colorimetry).
- 6.2: Titration of Juice
- Juice contains both citric and ascorbic acids. Citric acid is used as a natural preservative and provides a sour taste. Ascorbic acid is a water-soluble vitamin (vitamin C) that must be consumed regularly to ensure proper body function. There are many types of titrations. The most common are acid/base and oxidation reduction titrations. You will be using both of these types of titration in this lab.
- 6.3: Titration of Aspirin
- This lab consists of two parts. First, you will determine the precise concentration of a sodium hydroxide stock solution (by a process called “standardization”). Second, you will titrate a sample of your aspirin (an acid) with the standardized NaOH to determine the moles of acid in a given weight of your product. This will allow you to assess its purity.
- 6.4: Volumetric Analysis
- In this experiment, you will prepare a NaOH solution by diluting a more concentrated 6M NaOH solution. You will then standardize the NaOH solution—i.e., determine its concentration to a certain degree of accuracy—via titration. The standardized NaOH solution will be used to analyze and determine the concentration of a hydrochloric acid solution also via titration.
- 7.1: Atomic Theory: Spectroscopy and Flame Tests
- You will observe the flame emission colors for the following solutions: KCl, CaCl2, BaCl2, SrCl2, and LiCl. Since the chloride ion does not emit any color, you will be observing the flame emission color of the metallic cations. A demo will be carried out for the flame test for sodium ion since it can take more than 45 minutes to burn off the sodium residue from the flame test wire loop.
- 8.1: Calorimetry
- Calorimetry is the science of measuring heat flow, and heat is defined as thermal energy flowing from an object at a higher temperature to one at a lower temperature. Most physical and chemical changes are either exothermic or endothermic. Exothermic reactions release energy or heat and Endothermic reactions absorb energy or heat. In this experiment, the calorimeter used will consist of two nested Styrofoam coffee cups with a cover and a thermometer.
- 8.2: Heat of Combustion: Magnesium
- Hess’s Law states that when are going from a particular set of reactants to a particular set of products, the heat of reaction is the same whether the reaction takes place in one step or in a series of steps. In this experiment, you will use Hess’s Law to determine a heat of reaction that would be difficult to obtain by direct measurement—the heat of combustion of magnesium turnings.
- 9.1: Gas Laws and Analysis of an Antacid
- This experiment will apply the Ideal Gas Law and Dalton’s Law of Partial Pressures to determine the amount of sodium bicarbonate present in an Alka-Seltzer tablet. The reaction will be carried out, and the volume of carbon dioxide gas produced is collected and used to determine the mass percentage of sodium bicarbonate present in an Alka-Seltzer tablet. In the second part of the experiment an unknown solid is analyzed using the same method to determine the mass percentage of calcium carbonate pr
- 10.1: Spectroscopy and the Hydrogen Atom
- In this experiment, you will predict the wavelengths of light emitted by hydrogen atoms by using calculations from the Bohr model of hydrogen. Then you will use a simple spectroscope to observe the light emitted by hydrogen gas discharge tubes.
- 11.1: Molecular Geometry
- In this lab, you will study covalently-bonded molecules. You will draw Lewis electron-dot structures; use formal charges to identify a molecule’s most plausible structure; build models for various molecules to determine their molecular geometry and properties such as bond angles and atomic hybridization; use the polarity of individual bonds and the molecular geometry of a molecule to determine if the molecule is polar or nonpolar
- 11.2: Molecular Models
- For this lab you will use a model set that consists of balls representing the nucleus and the core electrons of an atom and sticks representing the bonds between the atoms. In order to build the model of a molecule or an ion it is convenient to proceed in a systematic way described here.
- 11.3: Molecular Models. Organic Molecules
- In the previous lab we considered molecules and ions for which one chemical formula corresponded to one chemical compound only. Not all chemical compounds are like that. For example, consider the formula C2H6O. It turns out that there is more than one compound with that chemical formula.
- 12.1: Soaps and Detergents
- In this experiment we will prepare soap and compare its properties to those of a commercial soap and a detergent.
- 12.2: Vapor Pressure of Liquids
- In this experiment, you will investigate the relationship between the vapor pressure of a liquid and its temperature. Pressure and temperature data will be collected using a gas pressure sensor and a temperature probe. Vapor pressures will be determined by subtracting atmospheric pressure from the total pressure.
- 12.3: Evaporation and Intermolecular Attractions
- In this experiment, you will study temperature changes caused by the evaporation of several liquids and relate the temperature changes to the strength of intermolecular forces of attraction.
- 12.4: Molar Mass of a Solid via Freezing Point Depression of a Solvent
- In this investigation masses of an unknown solute and known solvent will be measured and combined to form a solution. The freezing point depression of the solvent will be measured and the molality of the solution will be calculated.
- 12.5: Freezing Point Depression
- In the following experiments we will obtain the cooling curve of a pure solvent, acetic acid (HAc) and the equivalent curves after an unknown solute has been added to the solvent. From the measurements of ΔTf we will be able to determine the molecular mass of the unknown. In a couple of similar experiments with sucrose solutions we will measure the value of Kf for water. Finally we will calculate the van’t Hoff i factor for the electrolyte CaCl2.
- 13.1: Understanding Crystal Structures
- When a solid crystallizes, the atoms or ions that form it try to pack as tightly as possible. In the case of ions, repulsive forces between ions of the same kind of charge get minimized and attractive forces between ions of opposite charges get maximized.
- 13.2: Solid State Structure - The Cubic Lattice Systems
- In this investigation, you will first construct models of the three cubic unit cells representing a simple atomic solid, and assuming that atoms can be represented as rigid spheres, calculate the fraction of the volume that is empty or filled space. Then you will construct a model of the unit cells of sodium chloride and show its relationship to its simplest formula.
- 13.3: Growing Crystals
- How do crystals form? In this experiment you will grow crystals of a chemical AB (a solid at room temperature) where A+ is the cation and B-the anion.
- 14.1: Reaction Kinetics: Initial Rates via the Iodine Clock Reaction
- In this experiment, you will determine the rate law for a reaction and the effect of concentration on the rate of this reaction by studying the initial reaction rate at several reactant concentrations.
- 15.1: Le Chatelier’s Principle
- In this experiment you will observe shifts in equilibrium systems with changes in concentration and temperature and use Le Châtelier Principle’s to explain those shifts. For the first two systems, colored transition-metal complexes are used to monitor the amounts of reactants and products, and thus, determine the direction of equilibrium shifts based on color changes.
- 16.1: Weak Acids, Weak Bases and Salts
- Acid strength is defined by the equilibrium position for its dissociation. For strong acids, the equilibrium lies far to the right, as almost all of the HA molecules dissociate or ionize completely at equilibrium. The stronger the acid, the less likely its conjugate base can draw protons away from water molecules, i.e. the stronger the acid the weaker its conjugate base.
- 16.2: Using a Titration Curve for Identifying an Unknown Weak Acid
- In this experiment you will use a pH sensor connected to a Vernier LabQuest, a data collection device, to generate acid-base titration curves. You will investigate two types of acid-base titration systems: one involving a strong acid titrated by a strong base and the other involving the titration of an unknown weak monoprotic acid by a strong base.
- 16.3: Exploring Buffer Solutions
- Buffer solutions resist changes in pH upon addition of small amounts of acid or base. What is a buffer solution? It is essentially a mixture of a weak acid and a salt containing its conjugate base, OR a weak base and a salt containing its conjugate acid.
- 20.1: Synthesis and Analysis of a Copper (II) Coordination Compound
- In this multi-week experiment, you will synthesize a compound and then analyze it to determine its empirical formula. The substance you will prepare is a vividly colored coordination compound of copper. Based on the reagents used in the synthesis procedure, you can assume that the final compound contains copper(II), ammonia, sulfate, and water. In your analysis, you goal is to figure out the mole ratio of each component in the final compound.