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|a [cc by-nc] This item is licensed with the Creative Commons Attribution Non-Commerical License. This license lets others remix, tweak, and build upon this work non-commercially, and although their new works must also acknowledge the author and be non-commercial, they don’t have to license their derivative works on the same terms. |
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|a Santa Monica College. (2017). Online chemistry lab manual. LibreTexts. https://chem.libretexts.org/Ancillary_Materials/Laboratory_Experiments/Wet_Lab_Experiments/General_Chemistry_Labs/Online_Chemistry_Lab_Manual |
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|a 1: Measurements in the Laboratory (Experiment)
All measuring devices are subject to error, making it impossible to obtain exact measurements. Students will record all the digits of the measurement using the markings that we know exactly and one further digit that we estimate and call uncertain. The uncertain digit is our best estimate using the smallest unit of measurement given and estimating between two of these values. These digits are collectively referred to as significant figures.
2: Paper Chromatography of Gel Ink Pens (Experiment)
Chromatography is a method of physically separating mixtures into its individual components and is used to identify unknown components in mixtures. There are several types of chromatography; all types employ a mobile phase or eluent (liquid or gas), which is forced through a stationary phase (a solid or semi-solid). Mixtures are separated because some components will be more attracted to the stationary phase while some components will be more attracted to the mobile phase.
3: The Properties of Oxygen Gas (Experiment)
Oxygen is one of the most abundant elements on this planet. Our atmosphere is 21% free elemental oxygen. Oxygen is also extensively combined in compounds in the earths crust, such as water (89%) and in mineral oxides. Even the human body is 65% oxygen by mass. The objectives of this laboratory are: To generate (and collect) oxygen gas via the decomposition of hydrogen peroxide. To investigate the properties of oxygen, particularly as an agent of combustion.
4: Detection and Absorption of Ultraviolet Light (Experiment)
Solar energy (sunlight) contains light we can see, and some we cannot. Visible light has wavelengths of 750 to 400 nm. Ultraviolet (UV) light has shorter wavelengths, cannot be seen, and has higher energy. Infrared (IR) radiation is the major source of heat for Earth. Though UV is a fraction of sunlight, it can be damaging to living organisms. All of these are forms of energy in the electromagnetic spectrum.
5: Flame Tests and Atomic Spectra (Experiment)
The objectives of this lab are to: Perform flame tests of metal cations in order to observe their characteristic colors, Perform calculations to determine the frequency and energy of the emitted photons. Relate these results to the types of electronic transitions occurring in these elements. Observe and understand line emission spectra of atoms using gas-discharge tubes. Practice writing electron configurations for these (and other) elements.
6: Lewis Structures and Molecular Shapes (Experiment)
Non-metal atoms bond covalently, resulting in the formation of either neutral molecules or polyatomic ions. A covalent bond is formed when non-metal atoms share their valence electrons, which they do in order to achieve filled valence orbitals like their nearest noble gas neighbor. This means that most bonded non-metal atoms will acquire a total of eight valence electrons via the sharing process – often referred to as the octet rule.
7: Electrical Conductivity of Aqueous Solutions (Experiment)
Electrical conductivity is based on the flow of electrons. Highly ionized substances are strong electrolytes. Strong acids and salts are strong electrolytes because they completely ionize (dissociate or separate) in solution. The ions carry the electric charge through the solution thus creating an electric current. The current, if sufficient enough, will light one or both LEDs on a conductivity meter, shown at right.
8: Acid, Bases and pH (Experiment)
The objectives of this laboratory are: Set up and show how to use a pH indicator Determine the pH of common solutions Understand pH differences of acids and bases Learn to use a laboratory pH meter Understand relationship between pH and H+ ion concentration
9: Single Replacement Reactions and Batteries (Experiment)
During a chemical reaction both the form and composition of matter are changed. Old substances are converted to new substances, which have unique physical and chemical properties of their own.
10: Double Replacement Reactions (Experiment)
Reactions that can be classified as double replacements include precipitation reactions, neutralization reactions and gas forming reactions.
11: Synthetic Polymers and Plastics (Experiment)
The word “polymer” means “many units”. A polymer can be made up of many repeating units, which are small monomer molecules that have been covalently bonded. Figure 1 (from Chemistry in Context) shows a single monomer, and a polymer made of identical monomers linked together. A polymer can contain hundreds of monomers, totaling thousands of atoms. Plastic is a type of synthetic polymer. Currently, more than 60,000 plastics are manufactured for industrial and commercial purposes.
12: Making Soap - Saponification (Experiment)
Soap making has remained unchanged over the centuries. The ancient Roman tradition called for mixing rain water, potash and animal tallow.
1: Introducing Measurements in the Laboratory (Experiment)
Our knowledge of chemistry and chemical processes largely depends on our ability to obtain correct information about matter. Often this information is quantitative, in the form of measurements. In this lab, students will be introduced to some common measuring instruments so that they can practice making measurements, and to learn about instrument precision. Since all measuring devices are subject to some error, it is impossible to make exact measurements.
2: The Density of Liquids and Solids (Experiment)
OBJECTIVES To determine the density of pure water; To determine the density of aluminum (applying the technique of water displacement) and to use this value to determine the thickness of a piece of aluminum foil; To measure the mass and volume (via measured dimensions) of several cylinders of an unknown material, and to determine the density of this material via graphical analysis of the collected data.
3: Chemical Nomenclature (Experiment)
Ionic compounds are composed of ions. An ion is an atom or molecule with an electrical charge. Monatomic ions are formed from single atoms that have gained or lost electrons. Polyatomic ions are formed from molecules that have gained or lost electrons. Negative ions are called anions, and are formed when an atom or molecule gains electrons. All non- metals form negatively charged ions. Positive ions are called cations, and are formed when an species loses electrons.
4: The Properties of Oxygen Gas (Experiment)
Free elemental oxygen occurs naturally as a gas in the form of diatomic molecules. Oxygen exhibits many unique physical and chemical properties. In this lab, oxygen will be generated as a product of the decomposition of hydrogen peroxide. A catalyst is used to speed up the rate of the decomposition reaction, which would otherwise be too slow to use as a source of oxygen. The catalyst does not get consumed by the reaction, and can be collected for re-use once the reaction is complete.
5: The Composition of Potassium Chlorate (Experiment)
OBJECTIVES To experimentally determine the mass percent of oxygen in the compound potassium chlorate ( KClO3 ) via the thermal decomposition of a sample of potassium chlorate. To qualitatively demonstrate that the residue resulting from the decomposition of potassium chlorate is potassium chloride.
6: Single and Double Displacement Reactions (Experiment)
During a chemical reaction both the form and composition of matter are changed. Old substances are converted to new substances, which have unique physical and chemical properties of their own.
7: Mole Ratios and Reaction Stoichiometry (Experiment)
To determine these mole-to-mole ratios experimentally, a quantitative analysis of both reactions is required. Specifically, a pre-weighed mass of sodium bicarbonate/carbonate will be allowed to react with a slight excess of hydrochloric acid. The sodium chloride product will then be carefully retrieved, dried and weighed at the end of the reaction. This mass of collected sodium chloride is called an experimental yield.
8: Flame Tests of Metal Cations (Experiment)
9: Lewis Structures and Molecular Shapes (Experiment)
The objectives of this laboratory are: To practice drawing Lewis Structures for various covalently bonded molecules and polyatomic ions. To use model kits to construct these molecules/ions in order to explore their structure and shapes. To practice predicting molecular shapes (using VSEPR theory) and molecular polarity
10: Experimental Determination of the Gas Constant (Experiment)
A gas is the state of matter that is characterized by having neither a fixed shape nor a fixed volume. Gases exert pressure, are compressible, have low densities and diffuse rapidly when mixed with other gases. On a microscopic level, the molecules (or atoms) in a gas are separated by large distances and are in constant, random motion. Four measurable properties can be used to describe a gas quantitatively: pressure, volume, temperature, and mole quantity.
11: Titration of Vinegar (Experiment)
OBJECTIVES To determine the molarity and percent by mass of acetic acid in vinegar.
12: Equilibrium and Le Chatelier's Principle (Experiment)
A reversible reaction is a reaction in which both the conversion of reactants to products (forward reaction) and the re-conversion of products to reactants (backward reaction) occur simultaneously. A reversible reaction at equilibrium can be disturbed if a stress is applied to it and the reversible reaction will undergo a shift in order to re-establish its equilibrium. This is known as Le Chatelier’s Principle.
1: Using Excel for Graphical Analysis of Data (Experiment)
An important technique in graphical analysis is the transformation of experimental data to produce a straight line. If there is a direct, linear relationship between two variable parameters, the data may be fitted to the equation of line with the familiar form y=mx+b through a technique known as linear regression. The objective of this exercise is to use Excel to explore a number of linear graphical relationships.
2: The Densities of Solutions and Solids (Experiment)
Density is a fundamental physical property of matter. Physical properties are those characteristics of a substance that can be determined without changing the chemical identity of the substance. Other physical properties include melting point and solubility. In general, since different substances have unique densities, determining the density of an unknown substance can help identify it.
3: Paper Chromatography- Separation and Identification of Five Metal Cations (Experiment)
Most chemists and many other scientists must routinely separate mixtures and identify their components. The ability to qualitatively identify the substances found in a sample can be critical. For example, an environmental chemist investigating samples of polluted ground water will want to know which toxic ions might be present in a sample. Chromatography is one of the first tools used in such situations.
4: Inorganic Nomenclature (Experiment)
In this exercise you will practice naming and writing chemical formulas for many inorganic compounds, both ionic and molecular. Before beginning the exercise you should carefully read all the sections of your text (or notes) on the names and formulas of ionic compounds, simple covalent compounds, and acids. The following is a brief summary of the Nomenclature rules for each of these types of compounds.
5: Properties of Hydrates (Experiment)
It is generally possible to remove the water of hydration by heating the hydrate. Le Chatelier’s principle predicts that an addition of heat to an endothermic reaction (heat is a “reactant”) will shift the reaction to the right (product side). Heating will shift the equation of dehydration below to the right since it is an endothermic reaction. The residue obtained after heating, called the anhydrous compound, will have a different structure and texture and may have a different color than the hy
6: Types of Chemical Reactions (Experiment)
Matter undergoes three kinds of change: physical, chemical, and nuclear. While the composition of a chemical substance is not altered by physical changes (such as freezing and evaporation), chemical changes, or reactions, result in the formation of new substances when bonds are formed and/or broken. Some relatively simple but common types of chemical reactions are illustrated in this experiment. Examples and descriptions of each reaction type appear in the following section.
7: Gravimetric Analysis (Experiment)
Gravimetric analysis is a quantitative method for accurately determining the amount of a substance by selective precipitation of the substance from an aqueous solution. The precipitate is separated from the remaining aqueous solution by filtration and is then weighed. Assuming that the chemical formula for the precipitate is known and that the precipitation reaction goes all the way to completion, then the mass of the substance in the original sample can be determined.
8: Reaction Stoichiometry and the Formation of a Metal Ion Complex (Experiment)
The net result of a reaction can be summarized by a chemical equation. In order to write a chemical equation, a chemist must identify the reactants and products, as well as the ratios in which these species react and are produced, i.e., the stoichiometry of the reaction. When two or more reactants are mixed together, it is possible to determine whether a reaction occurs by observing whether any property of the mixture changes.
9: Evaluating the Cost-Effectiveness of Antacids (Experiment)
In this exercise, two commercially available antacids are evaluated and compared by: determining the number of moles of hydronium ions neutralized per gram of each antacid. calculating the cost effectiveness of each antacid.
10: Vitamin C Analysis (Experiment)
You will need to bring a powdered or liquid drink, health product, fruit samples, or other commercial sample to lab for vitamin C analysis. You will need enough to make 500 mL of sample for use in 3-5 titrations. Be sure the product you select actually contains vitamin C (as listed on the label or in a text or website) and be sure to save the label or reference for comparison to your final results. Be careful to only select products where the actual vitamin C content is listed.
11A: The Molecular Weight of Carbon Dioxide (Experiment)
OBJECTIVES To determine the molecular weight (molar mass) of carbon dioxide based on measurements of the pressure, temperature, volume and mass of a sample of the gas. To compare the experimental molecular weight to the theoretical molecular weight of carbon dioxide.
11B: The Dumas Method (Experiment)
In the early 19th century, Jean-Baptiste Dumas, a distinguished French chemist, created a relatively simple method for determining the molecular mass of a volatile substance. In this experiment we will use a modified version of his technique to determine the molecular mass of an unknown volatile liquid.
12: Calorimetry and Hess's Law (Experiment)
The combustion of a metal in oxygen produces the corresponding metal oxide as the only product. Such reactions are exothermic and release heat. Since it is difficult to measure the enthalpy of combustion of a metal directly, in this lab it will be determined indirectly by applying Hess’s Law of Heat Summation. Hess’s Law states that the enthalpy change of an overall process is equal to the sum of the enthalpy changes of its individual steps.
13: Measuring Manganese Concentration Using Spectrophotometry (Experiment)
Spectroscopy is one of the most powerful analytical techniques in modern science. Before the advent of spectrophotometric techniques, a chemist interested in determining the amount of a particular substance present in a sample had to analyze the sample via a series of chemical reactions specific to that species and then carefully weigh the products. Today, most routine assaying is done quickly and efficiently by means of spectroscopy.
14A: Atomic Emission Spectra (Experiment)
Electrons in atoms normally occupy the lowest energy states possible. Such an atom is said to be in the ground state. However, electrons can be excited to high energy states when they absorb excess energy. The excess energy can be provided by heat, light, or electrical discharge. The electrons then return to lower energy states, eventually returning all the way to the ground state. As the electrons return to lower energy states, they release their excess energy, often, in the form of light.
14B: Atomic Emissions Spectra - Pizza Box Version (Experiment)
Electrons in atoms normally occupy the lowest energy states possible. Such an atom is said to be in the ground state. However, electrons can be excited to high energy states when they absorb energy. This energy can be provided by heat, light, or an electrical discharge. The electrons will then return to lower energy states, eventually returning all the way to the ground state. As the electrons return to lower energy states, they release their excess energy, often in the form of light.
15: Using Periodic Properties to Identify Group 2A Cations and Group 7A Anions (Experiment)
When the solubilities of compounds containing various cations combined with a given anion are compared, a solubility trend that follows the order in the periodic table is expected. For example, for the solubilities of the sulfate salts, the solubility is expected either to increase or decrease as we go down the alkaline earth family. These solubility properties will be used to identify an unknown compound containing a cation.
16: Qualitative Analysis of Everyday Chemicals (Experiment)
This lab introduces qualitative analysis, the area of chemistry concerned with the identification of substances by their physical and chemical properties. Identifying unknown substances is an important part of chemistry, with applications in fields such as medicine and environmental chemistry. Materials can be characterized by observing their physical and chemical properties and/or by instrumental methods.
17: VSEPR Theory and Shapes of Molecules (Experiment)
The VSEPR (Valence Shell Electron Pair Repulsion) model is used to predict the geometry of molecules based on the number of effective electron pairs around a central atom. The main postulate for the VSEPR theory is that the geometrical structure around a given atom is principally determined by minimizing the repulsion between effective electron pairs. Both the molecular geometry and the polarity of individual bonds then determine whether the molecule is polar or not.
18: Introduction to the Structures and Isomerism of Simple Organic Molecules- Description and Modeling (Experiment)
Molecules that have the same molecular formula but are not identical are called conformers or isomers. Conformers differ only by the angle of rotation about a single bond(s) however isomers have different structural or spatial arrangements.
1: Chemical Kinetics - The Method of Initial Rates (Experiment)
The objectives of this experiment are to determine the rate law of a chemical reaction using the Method of Initial Rates, to determine the activation energy of the reaction by finding the value of the rate constant, k , at several temperatures, and to observe the effect of a catalyst on the reaction rate.
2: Determination of Kc for a Complex Ion Formation (Experiment)
The objectives of this experiment are to find the value of the equilibrium constant for formation of FeSCN2+ by using the visible light absorption of the complex ion and to confirm the stoichiometry of the reaction.
3: Le Chatelier's Principle (Experiment)
The objectives of this experiment are to perturb chemical reactions at equilibrium and observe how they respond, to explain these observations using Le Chatelier’s Principle, and to relate Le Chatelier’s Principle to the concept of coupled reactions.
4: Determining the Equivalent Mass of an Unknown Acid by Titration (Experiment)
The objectives of this experiment are to perform an analytical titration, to standardize a basic solution, and to determine the equivalent mass of an unknown acid.
5: pH Measurement and Its Applications (Experiment)
The objectives of this experiment are to measure the pH of various solutions using pH indicators and meter, to determine the value of Ka for an unknown acid, to perform a pH titration (OPTIONAL, if time permits), and to create and study the properties of buffer solutions.
6: Qualitative Analysis of Group I Ions (Experiment)
The objectives of this experiment are to follow a classic analytical scheme to separate and identify the ions in a known mixture of Group 1 cations, and then to then apply this scheme to identify the ions in an unknown mixture of Group 1 cations.
7: Qualitative Analysis of Group III Ions (Experiment)
The objectives of this experiment are to follow a classic qualitative analysis scheme to separate and identify the ions in a known mixture of Group III cations, and then to apply this scheme to identify the Group III cations present in an unknown sample.
8: Qualitative Analysis of Anions Using Spot Plates (Experiment)
The objective of this experiment is to use spots tests to identify common anions in an aqueous solution.
9: Electrolytic Determination of Equivalent Mass (Experiment)
The objective of this experiment is to use electrolysis to determine the equivalent mass of an unknown metal.
10: Determination of the Molar Mass by Freezing Point Depression (Experiment)
The objective of this experiment is to determine the molar mass of an unknown solid using the colligative property of freezing point depression.
11: Solubility and Borax (Experiment)
The objectives of this experiment are to learn about the solubility and solubility equilibria, to see how equilibrium constants change with temperature, and to determine the values of ΔHo, ΔSo, and ΔGo for a reaction.
-Online Chemistry Lab Manual |
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|a Item consists only of chapters 9, 10, 11, and 12. |
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|a Electronic reproduction. |c Santa Monica College, |d 2020. |f (Open-NJ) |n Mode of access: World Wide Web. |n System requirements: Internet connectivity; Web browser software. |
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|u https://chem.libretexts.org/Bookshelves/Ancillary_Materials/Laboratory_Experiments/Wet_Lab_Experiments/General_Chemistry_Labs/Online_Chemistry_Lab_Manual |y External Link |