Name: organic lab glassware and safe handling
Uploaded: 2020-03-26T07:22:27.000Z
Duration: 3 min 8 s
Channel: JoVE

K12 Standards

Texas Essential Knowledge and Skills

High School

Chemistry

CHEM.1

CHEM.1.D

Basic Organic Chemistry Techniques

Bei Laborverfahren in der organischen Chemie werden in der Regel Standardglasgeräte und -techniken verwendet. Becher und Erlenmeyerkolben werden häufig zum einfachen Mischen und Halten von Lösungsmitteln verwendet. Kolben mit rundem Boden, die entweder einen kurzen oder einen langen Hals haben, werden für Reaktionen unter hoher Hitze oder Vakuum verwendet. Dies liegt daran, dass die runde Form unter diesen Bedingungen widerstandsfähiger gegen Rissbildung ist.
Das Erhitzen von Reaktionen ist ein gängiges Laborverfahren. Für organische Verbindungen wird ein Bunsenbrenner jedoch in der Regel nicht eingesetzt, da diese brennbar sind. Beim Erhitzen einer Reaktion in einem Becherglas oder Erlenmeyerkolben wird typischerweise eine Heizplatte mit einem Magnetrührer verwendet. Beim Erhitzen einer Reaktion in einem Kolben mit rundem Boden wird ein Wasserbad oder eine Heizhaube verwendet, um die Form des Kolbens aufzunehmen.
Viele Reaktionen müssen für eine bestimmte Zeit auf eine bestimmte Temperatur erhitzt werden, um ablaufen zu können. Diese Reaktionen werden unter Reflux durchgeführt. Bei einem Rückflussaufbau wird ein Kolben mit rundem Boden verwendet, der ein Lösungsmittel enthält, dessen Siedepunkt sich mit der optimalen Temperatur der Reaktion überschneidet. Ein Kondensator wird auf den Kolben aufgesetzt, und kaltes Wasser tritt am unteren Arm ein und tritt aus dem oberen Arm aus. Beim Erhitzen und Rühren des Gemisches verdampft das Lösungsmittel und kondensiert dann wieder im Kolben, wobei das Reaktionsvolumen erhalten bleibt.
Eine weitere gängige Technik, die im Labor für organische Chemie verwendet wird, ist die Filtration, eine Methode zur Trennung von Feststoffen aus Flüssigkeiten. Die Schwerkraftfiltration ist die einfachste Filtrationstechnik zur Abscheidung von körnigen unlöslichen Feststoffen. Dieser Aufbau besteht aus einem Erlenmeyerkolben, einem konischen Trichter und einem gefalteten Stück Filterpapier. Das Gemisch wird in den Trichter gegossen und die Flüssigkeit gelangt in den Kolben, das sogenannte Filtrat. Die Feststoffe verbleiben auf dem Filterpapier.
Eine schnellere Filtrationstechnik ist die Vakuumfiltration. Dabei wird ein Büchner-Trichter über einen Gummiadapter mit einem Filterkolben verbunden. Der Filterkolben sieht aus wie ein Erlenmeyerkolben, hat aber einen Seitenarm, der den Kolben über einen Vakuumschlauch mit dem Vakuum verbindet. Dann wird ein flaches Stück Filterpapier in den Trichter gelegt und leicht angefeuchtet, bevor das Vakuum langsam eingeschaltet wird. Die Flüssigkeit wird durch das Filterpapier in den Kolben gesaugt, während der Feststoff auf dem Filterpapier zurückgehalten wird.
 In diesem Labor führen Sie eine einfache Reaktion zur Bildung von Benzoesäure durch, die es Ihnen ermöglicht, einfache Techniken der organischen Chemie wie das Wiegen von Feststoffen, das Messen des Volumens und die Durchführung von Vakuumfiltration zu üben. Anschließend üben Sie die Reflextechnik mit Tetrahydrofuran.

grundlegende techniken der organischen chemie

Glaswaren in der organischen Chemie
Es gibt Standard-Glaswaren, die im Labor für organische Chemie verwendet werden. Becher und Erlenmeyerkolben werden typischerweise zum einfachen Mischen oder zum Halten von Lösungsmitteln verwendet, sollten jedoch nicht zur Volumenmessung verwendet werden, es sei denn, es wird nur ein ungefähres Volumen benötigt. Gläser können in folgende Kategorien eingeteilt werden:
<ol>
	<li style="font-size:17px">Volumetrische Glaswaren – Dazu gehören Glaswaren wie Messzylinder, volumetrische Glaspipetten und Messkolben. Der Zweck dieser Artikel besteht darin, ein genaues Volumen eines Stoffes zu messen oder abzugeben. Ein Messzylinder wird in der Regel zur Volumenmessung in einem organischen Labor verwendet. Der Messzylinder hat eine lange zylindrische Form mit Volumenmarkierungen an der Seite. Es ist wichtig, einen möglichst kleinen Messzylinder für das benötigte Volumen zu verwenden, um Fehler zu minimieren. Zum Beispiel ist ein 25-ml-Messzylinder ausreichend, um 20 mL Reagenz zu messen, aber er ist nicht genau, um ein kleineres Volumen, wie 5 mL, zu messen. Verwenden Sie jedoch keinen 25-ml-Messzylinder, um 100 mL zu messen, indem Sie vier 25-ml-Volumina messen. Es ist besser, den 100-ml-Messzylinder zu verwenden.</li>
	<li style="font-size:17px">Reaktionseindämmung – Diese spezialisierten Teile können verwendet werden, um eine organische chemische Reaktion zu beherbergen. Kolben mit rundem Boden sind ein Beispiel für diese Glaswaren. Im Gegensatz zu Erlenmeyerkolben bieten Rundkolben eine größere Oberfläche und sorgen daher für eine gleichmäßigere Erwärmung oder Abkühlung. Kolben mit rundem Boden werden verwendet, um Reaktionen unter hoher Hitze oder Vakuum durchzuführen, da ihre runde Form widerstandsfähiger gegen Rissbildung ist. In diese Kategorie fallen auch spezielle Glaswaren, die als Kondensatoren bekannt sind und dazu verwendet werden, gasförmige Dämpfe zu sammeln und sie wieder in die zu sammelnde flüssige Phase zu kondensieren.</li>
	<li style="font-size:17px">Filtration – Diese Glasstücke werden hauptsächlich verwendet, um Ausfällungen aus einem Reaktionsgemisch zu isolieren. Um feste Ausfällungen zu isolieren, ist eine Filtrationsapparatur erforderlich. Der einfachste Aufbau verwendet einen Glastrichter, der an einem Erlenmeyerkolben befestigt ist. Im Inneren des Trichters befindet sich ein Stück Filterpapier. Das Reaktionsgemisch, das den Feststoff enthält, wird in den Trichter gegossen, und die Schwerkraft zieht die Flüssigkeit in den Kolben, wobei der Feststoff zurückbleibt. Dies wird als Schwerkraftfiltration bezeichnet. Diese Konfiguration kann jedoch einen langen Zeitraum in Anspruch nehmen, um den Volumenkörper zu filtern. Bei einer Vakuumfiltration wird der Erlenmeyerkolben durch einen Isolierkolben mit Seitenarm und der Glastrichter durch einen Porzellanfiltertrichter, den sogenannten Büchner-Trichter, ersetzt. Dieser Seitenarm ist an einer Vakuumquelle befestigt. Wie zuvor wird das Reaktionsgemisch in den Filtertrichter gegossen und die Filtration durch die Kraft des Vakuums unterstützt.</li>
	<li style="font-size:17px">Trennung – Diese speziellen Kolben oder Trichter werden hauptsächlich für Flüssig-Flüssig-Phasenextraktionen verwendet, eine Technik, die die Trennung von Produkten durch die Verwendung von Lösungsmitteln mit unterschiedlichen Polaritäten oder Hydrophobien ermöglicht. Diese nicht mischbaren Flüssigkeiten bilden eine heterogene Lösung, die sich in zwei Phasen trennt. Scheidetrichter haben am Boden ein Ventil, das als Absperrhahn bezeichnet wird und die Trennung der Phasen ermöglicht, indem sie in einen neuen Behälter gegossen werden.</li>
	<li style="font-size:17px">Transport – Diese Glaswaren bestehen hauptsächlich aus Flaschen oder Fläschchen mit entsprechendem Verschluss. Diese Gläser werden vor allem für den sicheren Transport von potenziell gefährlichen Gütern verwendet.</li>
	<li style="font-size:17px">Allgemeine Verwendung – Diese Kategorie besteht aus Glaswaren wie Bechern, Erlenmeyerkolben, Glasstäben und anderen verschiedenen Stücken.</li>
</ol>
Wiegen von organischen Reagenzien
Organische Reagenzien können in verschiedenen Formen vorliegen, und es ist wichtig, eine gute Labortechnik zu praktizieren, wenn man diese Reagenzien für die Verwendung in Experimenten erhält. Überprüfen Sie immer das Sicherheitsdatenblatt eines Reagenzes, um potenzielle Gefahren bei der Arbeit damit zu ermitteln. Feste Reagenzien sollten mit Waagschalen oder Wägepapier und der entsprechenden Art von Waage abgemessen werden.
Wenn eine genaue Messung erforderlich ist, verwenden Sie eine Analysenwaage. Wenn eine große Menge an Reagenz verwendet werden soll, verwenden Sie eine Topladerwaage. Legen Sie ein Wägeschiffchen oder Wägepapier auf die Waage und drücken Sie die "Tara"-Taste. Die Tara-Funktion macht die Masse des Wägepapiers ungültig. Verwenden Sie immer einen Spatel, um feste Reagenzien aus dem Vorrat auf das Wägeschiffchen zu übertragen. Verwenden Sie niemals denselben Spatel für verschiedene Reagenzien, da dies die Stammreagenzien verunreinigen kann. Und geben Sie niemals überschüssiges Reagenz in die Vorratsflasche zurück. Entsorgen Sie es stattdessen auf die entsprechende Weise wie angewiesen.
Wenn du den Feststoff in das entsprechende Gefäß umfüllst, gieße den Feststoff vorsichtig mit einem kleinen Trichter hinein. Wenn Feststoffe übrig bleiben, verwenden Sie eine kleine Menge des Lösungsmittels, das auf dem Wägeschiffchen verwendet wird, und füllen Sie es in den Kolben um.
Organische Flüssigkeiten können mit volumetrischen Glasgeräten, wie z. B. einem Messzylinder, gemessen werden. Berechnen Sie das Volumen der Flüssigkeit anhand ihrer Dichte und tarieren Sie dann den Reaktionskolben auf der Waage. Mit einer Pipette oder einem Messzylinder wird das Volumen direkt in den Reaktionskolben übertragen. Befolgen Sie die Richtlinien für die jeweilige Art von Glaswaren. Verwenden Sie niemals dasselbe Glasteil für mehrere Reagenzien und geben Sie niemals überschüssiges Reagenz in die Flüssigvorratsflaschen zurück. Für Flüssigkeiten, c
Erhitzen organischer Reaktionen
Manchmal ist Hitze erforderlich, um eine organisch-chemische Reaktion zu ermöglichen. In der allgemeinen Laborumgebung wird die Hitze üblicherweise mit einem Bunsenbrenner mit direkter Gasflamme angewendet. In Laboren der organischen Chemie kann die offene Flamme eines Bunsenbrenners zu einer gefährlichen Situation führen. Organische Reagenzien, insbesondere Lösungsmittel, sind leicht brennbar und bilden zum Teil relativ leicht Dämpfe. Aus diesem Grund werden Bunsenbrenner in Laboratorien der organischen Chemie nicht eingesetzt.
Stattdessen werden Heizbäder, Heizplatten oder Hauben verwendet, um eine indirekte Wärmequelle bereitzustellen. Heizplatten mit Magnetrührfunktion werden zum Erhitzen von Bechern und Erlenmeyerkolben verwendet. Heizhauben sind so konzipiert, dass sie einen Rundkolben mit unterschiedlichen Volumina sicher erwärmen können. Wasserbäder werden verwendet, wenn die Temperatur der Reaktion 100 °C nicht überschreiten muss. Eine Reaktion in Glaswaren wird in ein Wasserbad getaucht, das durch eine Heizplatte erhitzt wird. Die Temperatur wird auf den entsprechenden Bereich moduliert. Wenn die erforderliche Temperatur 100 °C, aber nicht 250 °C überschreiten soll, kann ein Silikonmantel verwendet werden. Wenn die Temperatur 250 °C überschreiten muss, kann ein Sandbad verwendet werden.
Viele Reaktionen erfordern es, über lange Zeiträume auf eine bestimmte Temperatur erhitzt zu werden, damit sie ablaufen können. Wenn eine Reaktion jedoch über einen längeren Zeitraum erhitzt wird, kann das Lösungsmittel verdampfen, was zu einem Verlust der Reaktionslösung führt. Stattdessen wird häufig ein Rückflussaufbau verwendet, bei dem ein Kolben mit rundem Boden verwendet wird, der ein Lösungsmittel enthält. Der Siedepunkt des Lösungsmittels überschneidet sich mit der optimalen Temperatur der Reaktion. Der Rundkolben wird auf einen Ständer geklemmt, und ein Kondensator wird auf den Kolben aufgesetzt. Kaltes Wasser fließt durch den Kondensator vom unteren Arm zum oberen Arm, während das Gemisch erhitzt und gerührt wird. Beim Erhitzen des Gemisches verdampft das Lösungsmittel und kondensiert dann wieder im Kolben, wobei das Reaktionsvolumen erhalten bleibt.

Grundlegende Techniken der organischen Chemie

Glaswaren in der organischen Chemie
Es gibt Standard-Glaswaren, die im Labor für organische Chemie verwendet werden. Becher und Erlenmeyerkolben sind ...

Education

Lehre

JoVE Lab Manual

Chemie

organic lab glassware and safe handling

Organic chemistry labs use specific glassware, careful weighing steps, and controlled heating to keep reactions safe and accurate. Beakers and Erlenmeyer flasks are often used for mixing or holding solvents, but they are not meant for measuring volume unless only an approximate amount is needed.

Volumetric glassware is used when a precise volume matters. This group includes graduated cylinders, volumetric pipettes, and volumetric flasks. A graduated cylinder is commonly used in the organic lab because it has volume markings along a long cylinder. It is best to choose the smallest cylinder that can measure the needed amount. For example, a 25-mL graduated cylinder can measure 20 mL, but it is not accurate for a small volume like 5 mL. It is also better to use a 100-mL graduated cylinder for 100 mL than to measure four separate 25-mL portions.

Other glassware is built to hold reactions or help them proceed under specific conditions. Round-bottom flasks provide more surface area than Erlenmeyer flasks and allow more even heating or cooling. They are useful for reactions under high heat or vacuum because their round shape is less likely to crack. Condensers are another important type of glassware. They collect vapor and turn it back into liquid so it can be collected again.

Glassware is also used for filtration, separation, transport, and general lab work. To remove solid precipitates, a simple gravity filtration setup uses a glass funnel, filter paper, and an Erlenmeyer flask. The liquid passes through while the solid stays behind, but the process can take a long time. A vacuum filtration setup is faster and uses a vacuum flask with a side arm, a B&amp;uuml;chner funnel, and a vacuum source. For liquid-liquid phase extractions, separatory funnels are used to split immiscible liquids into two layers. These flasks and funnels separate products by using solvents with different polarities or hydrophobicities. The stopcock at the bottom lets the layers be drained into a new container. Bottles and vials with matching caps are used for safe transport of hazardous material. Beakers, Erlenmeyer flasks, glass rods, and other mixed-purpose items fall into the general use category.

Organic reagents also need careful handling during weighing and transfer. Students should always check the reagent MSDS, or material safety data sheet, for hazards first. Solid reagents are measured on weighing boats or weighing paper with the correct balance. Use an analytical balance for precise mass and a top-loading balance for larger amounts. After placing the weighing boat on the balance, press tare to zero out its mass. Transfer solids with spatulas, but never use the same spatula for different reagents. Do not return extra reagent to the stock bottle. Instead, discard it as instructed. A small funnel can help move the solid into the reaction vessel, and any residue on the boat can be rinsed in with a small amount of the solvent being used.

Liquids are measured with volumetric glassware such as a graduated cylinder. Their volume can be calculated from density, and the reaction flask can be tared on the balance before transfer. A pipet or graduated cylinder is then used to add the liquid directly to the flask. The same piece of glassware should not be reused for multiple reagents, and excess liquid should never go back into the stock bottle. When heat is needed for an organic reaction, a Bunsen burner is avoided because organic solvents and vapors can ignite easily. Instead, labs use hotplates, heating baths, or heating mantles. Hotplates with magnetic stirring heat beakers and Erlenmeyer flasks. Heating mantles are made for round-bottom flasks. Water baths are used when the reaction temperature stays below 100 &amp;deg;C. Silicone mantles are used when the temperature must be above 100 &amp;deg;C but below 250 &amp;deg;C, and sand baths are used above 250 &amp;deg;C. For long heating times, a reflux setup helps prevent solvent loss. A round-bottom flask with solvent is clamped to a stand, a condenser is attached, and cold water flows from the bottom arm to the top arm while the mixture is heated and stirred. The solvent vapor condenses and returns to the flask, which keeps the reaction volume steady.

Organic Lab Glassware and Safe Handling

lab techniques

Measuring with Accuracy in the Lab

Measuring with accuracy in the lab starts with careful records, the right tools, and correct reading of data. Scientists use lab notebooks to record how an experiment was done. These notes include the amounts of materials used and each step of the procedure. Without that record, an experiment cannot be repeated in the same way. Balances and glassware are used to measure solids and liquids for experiments. The precision of a measurement depends on the equipment used. Digital balances show the...

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Graphs, Curve Fit, and Standard Deviation

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stoichiometry, product yield, and limiting reactants

stoichiometry-product-yield-and-limiting-reactants

Balancing Equations and Reactant Limits

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redox reactions

Oxidation States in Redox Reactions

Oxidation states help identify redox reactions. In a redox reaction, oxidation is the loss of one or more electrons, and reduction is the gain of one or more electrons. These reactions are often tracked by changes in oxidation state, also called oxidation number. Each atom in a molecule has an oxidation state. This number shows how oxidized an atom is compared with its free elemental form. It is written as the charge an atom would have if every bond were purely ionic. In that model, bonding...

ideal gas law

Gas Laws Behind the Ideal Gas Equation

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acid and base concentrations

Acids, Bases, and pH in Titration

Acids, bases, and pH explain how acidic or basic a solution is. An Arrhenius acid releases hydrogen ions when it dissolves in water, while an Arrhenius base releases hydroxide ions. These reactions also create conjugate partners: an acid forms a conjugate base after losing hydrogen, and a base forms a conjugate acid after losing hydroxyl. Every acid has a conjugate base, and every base has a conjugate acid. pH measures the amount of hydrogen ions in a solution. The pH scale runs from 0 to 14...

buffers

Buffer pH and the Common Ion Effect

Buffer solutions help keep pH steady when acids or bases are added. In water, an Arrhenius acid (HA) dissociates into hydrogen ions, H+, and a conjugate base, A-. More hydrogen ions make a solution more acidic and lower its pH. An Arrhenius base (BOH) dissociates into a conjugate acid, B+, and hydroxide ions, OH-. Strong acids and strong bases usually change pH a lot because they react completely in water and raise the amount of H+ or OH-. Buffers reduce those pH changes. A buffer usually...

enthalpy of reaction

Reaction Heat, Hess’s Law, and Calorimetry

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solubility

Solubility in Water and Other Solvents

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metal flame emission

Flame Test Metal Color Clues

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balmer series

Hydrogen Emission Lines

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beer's law

Absorbance Spectra and Beer-Lambert Analysis

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concentration dependence

Reaction Order and Rate Constants

Chemical kinetics describes the speed of a chemical reaction. The rate depends on the reaction mechanism, the complexity of the reaction, and the number of reactants involved. Reactant concentration also affects how fast a reaction happens. The rate law is the experimental relationship that connects these factors to reaction rate. In the rate law, each reactant contributes through a reaction order. The general form is r = k[A]^m[B]^n for aA + bB + ... → cC. Here, r is the reaction rate, k is...

temperature dependence

Reaction Rate, Arrhenius, and Catalysts

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galvanic cells

Battery Power from Redox Reactions

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electrolytic cells

Electroplating with Electrolytic Cells

Electrochemistry links electrical energy with chemical change, and electrolytic cells show how electricity can drive a nonspontaneous reaction. In these reactions, electrons move from one species to another. The key chemistry is a redox reaction, or oxidation-reduction reaction, which happens in two half-reactions. Oxidation is the loss of electrons, and reduction is the gain of electrons. The substance that loses electrons is the reducing agent, and the substance that gains electrons is the...

proper lab notebook keeping

Recording a Reproducible Lab Experiment

Accurate lab notebook records are essential in science and organic chemistry labs. Without clear notes, descriptions, quantities, and observations, an experiment cannot be repeated or checked. Good record keeping supports reproducibility, which means other people can follow the same work and get similar results. A laboratory notebook is useful in school labs, research settings, and industry. It can also become a legal record when an idea, process, substance, or technique is patented and...

basic organic chemistry techniques

Organic chemistry labs use specific glassware, careful weighing steps, and controlled heating to keep reactions safe and accurate. Beakers and Erlenmeyer flasks are often used for mixing or holding solvents, but they are not meant for measuring volume unless only an approximate amount is needed. Volumetric glassware is used when a precise volume matters. This group includes graduated cylinders, volumetric pipettes, and volumetric flasks. A graduated cylinder is commonly used in the organic lab...

melting points

How Impurities Change Melting Points

Melting point helps identify an organic compound by showing the temperature where a solid turns into a liquid at 1 atmosphere of pressure. It is a physical property, like solubility, density, color, and electronegativity. Because the exact start of melting is hard to measure, the result is reported as a range. The lower end is when the first drops of liquid appear. The upper end is when the last solid has melted. Scientists compare this range with literature values to help identify a compound. <br...

boiling points

Boiling Point and Vapor Pressure

Boiling point and vapor pressure are key physical properties of a liquid. For a pure compound, the boiling point can help identify the substance. In experiments, the boiling point is usually recorded as a range because exact values are hard to measure and may differ by a few degrees from the literature value. Vapor pressure explains why a liquid boils. In a sealed container, some molecules at the liquid surface gain enough energy to escape into the gas phase. At the same time, some gas...

recrystallization

Purifying Crystals by Solubility

Purifying crystals by solubility is a key organic chemistry technique. Recrystallization uses differences in solubility to separate a desired solid product from starting materials, solvent, and impurities. It is one of the three standard purification methods, along with distillation and extraction. Solubility is the maximum amount of a substance that can dissolve in a fixed volume of solvent at a given temperature. Different solutes dissolve in different solvents, and their behavior can vary...

extraction

Separating Mixtures with Solvent Extraction

Solvent extraction is a common way to separate and isolate a target compound in organic chemistry. In this process, a solute moves from one phase to another so it can be separated from unreacted starting materials or impurities. Extraction is also useful when a product is dissolved in a reaction solvent that is hard to remove by evaporation, such as a solvent with a high boiling point. There are three main types of extraction. In solid-liquid extraction, the solute moves from a solid phase...

simple distillation

Separating Liquids by Boiling Point

Separating liquids by boiling point is the goal of distillation. A miscible mixture contains liquids that mix evenly, and it can be heated so that the more volatile liquid evaporates first. Volatility is a liquid’s tendency to vaporize, and boiling begins when bubbles form in the liquid phase. In a closed container, liquid and vapor can reach equilibrium, which means the rate of vaporization equals the rate of condensation. The pressure from the vapor above the liquid is called vapor pressure.

steam distillation

Steam Distillation and Low-Boiling Separation

Steam distillation is a separation method for temperature-sensitive organic compounds. It works best when the organic compound is immiscible in water, meaning the two liquids do not mix. The method helps remove the organic molecule from a non-volatile contaminant without using the higher temperatures needed for many other separations. In steam distillation, the immiscible mixture is heated until both water and the volatile organic compound distill together. The vapor rises to a condenser,...

thin-layer chromatography

TLC Separation by Polarity

Thin-layer chromatography (TLC) separates compounds in a mixture by polarity. It uses the same basic parts as other chromatography methods: a stationary phase, a mobile phase, and the solute. In TLC, the stationary phase is a thin coating on a plate instead of material packed into a column. The stationary phase in most TLC systems is polar silica gel, a form of silicon dioxide. Its surface has OH groups that can form hydrogen bonds. The sample is first spotted on a pencil start line with a...

column chromatography

Separating Mixtures by Polarity

Column chromatography separates compounds in an organic chemistry lab by using differences in physical properties. It is especially useful for microscale separations when less than 10 grams of material is available for analysis. The method can separate a mixture based on solubility, polarity, hydrophobicity, size, and charge. Any chromatography system has three main parts: the stationary phase, the mobile phase, and the sample mixture. In column chromatography, the stationary phase is usually...

hydrolysis of an ester

Soap Formation from Triglycerides

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synthesis of luminol

Luminol Chemiluminescence in Forensics

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esterification

Ester Formation and Everyday Fragrances

Esters are organic compounds with a carbonyl group attached to an oxygen that connects to another alkyl or aryl group. Their general formula is RCOOR'. They are often made by reacting a carboxylic acid with an alcohol in an esterification reaction. In this process, the hydroxyl group of the acid is replaced by an alkyl or aryl group. Many simple esters have familiar fruit and flower smells because their structures are small and less complex. Formic acid and methanol can combine to form methyl...

identification of unknown aldehydes and ketones

identification-of-unknown-aldehydes-and-ketones

Carbonyl Tests for Aldehydes and Ketones

Aldehydes and ketones are carbonyl compounds, which means they contain a C=O functional group. A ketone has two alkyl or aryl groups attached to the carbonyl carbon. Acetone is the simplest ketone, with two methyl groups. An aldehyde is similar, but it has at least one hydrogen attached to the carbonyl carbon. Formaldehyde is the simplest aldehyde, and acetaldehyde has one hydrogen and one methyl group. The carbonyl carbon in both aldehydes and ketones is electrophilic because the oxygen atom...

uv-vis spectroscopy of dyes

How Dyes Absorb Visible Light

Dyes absorb visible light because their molecular structure lets them interact with specific wavelengths. When light hits a substance, some light is absorbed and the rest is reflected or transmitted. The color we see depends on the wavelength that is reflected. A blue substance reflects blue light, around 430 to 480 nm, and absorbs the complementary orange region, around 590 to 630 nm. Compounds that do not absorb in the visible range appear colorless to the human eye. Light also has energy and...

identifying alcohols

Alcohol Tests for Primary, Secondary, and Tertiary

Alcohol tests can help sort alcohols by structure and reactivity. Alcohols are organic molecules with a hydroxyl group attached to an alkyl or aryl group, written as ROH. If the carbon with the hydroxyl group has one R group, the alcohol is primary. If it has two R groups, it is secondary. If it has three R groups, it is tertiary. Alcohols can also be aromatic when they contain a benzene ring. Phenol is the simplest aromatic alcohol. To identify an alcohol, chemists can use its chemical...

chemistry

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Learn how high school organic chemistry labs use glassware, filtration, separatory funnels, weighing tools, and safe heating methods for reactions.

Organic Lab Glassware and Safe Handling | JoVE K12

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Scientific Laws and Theories

Scientific Laws

In science, a law is defined as a concise, verbal or mathematical, statement that summarizes a vast number of experimental observations. ...

The Scientific Method

Chemistry is an empirical science. Scientists often pose questions to understand the chemistry in everyday life and seek answers to these questions. To ...

CHEM.1.A

What is an Experiment?

An experiment is a planned activity carried out under controlled conditions. The purpose of an experiment is to investigate the relationship between two ...

Study Design in Statistics

A study design is a set of techniques that allow a researcher to collect and analyze data from different variables defined for a specific research ...

Observational Studies

Observational studies are a type of analytical study where researchers observe events without any interventions. In other words, the researcher does not ...

Experimental Designs

An experimental design is a systematic process that allows researchers to evaluate the relationship between dependent and independent variables. There are ...

Randomized Experiments

The randomization process involves assigning study participants randomly to experimental or control groups based on their probability of being equally ...

Crossover Experiments

Crossover experiments, also called the repeated-measurements design, is a study design in which all experimental units are exposed to all treatments in ...

Controls in Experiments

When conducting an experiment, it is crucial to have control to reduce bias and accurately measure the dependent variables. It also marks the results more ...

Bias

Bias refers to any tendency that prevents a question from being considered unprejudiced. In research, bias occurs when one outcome or answer is selected ...

Blinding

Blinding is a commonly used method of not telling participants which treatment a subject is receiving. Blinding is a critical part of a randomized control ...

CHEM.1.B

Proper Personal Protective Equipment

Robert M. Rioux &#38; William A Elliott, Pennsylvania State University, University Park, PA
Hazards are many and varied in the laboratory, but the right ...

Emergency Eyewash and Shower Stations

Robert M. Rioux, Pennsylvania State University, University Park, PA
The Occupational Safety and Health Administration (OSHA) mandates that an emergency ...

Electrical Safety

Robert M. Rioux &amp; Suprita Jharimune, Pennsylvania State University, University Park, PA
Among the many hazards present in the laboratory, electrical ...

Working with Centrifuges

Source: Robert M. Rioux &amp; Suprita Jharimune, Pennsylvania State University, University Park, PA
Earth's gravitational force is capable of separating ...

Working with Hot and Cold Sources

Source: Robert M. Rioux &amp; Suprita Jharimune, Pennsylvania State University, University Park, PA
Working with extreme temperatures, both high and low, ...

guidelines-in-case-of-a-laboratory-emergency

Guidelines in Case of a Laboratory Emergency

Robert M. Rioux &amp; Zhifeng Chen, Pennsylvania State University, University Park, PA
The most common laboratory emergencies include chemical spills, ...

chemical-storage-categories-hazards-and-compatibilities

Chemical Storage: Categories, Hazards And Compatibilities

Source: Robert M. Rioux &amp; Taslima A. Zaman, Pennsylvania State University, University Park, PA
While the use of various chemicals in experimental ...

Safe Handling of Mineral Acids

Source: Robert M. Rioux &#38; Taslima A. Zaman, Pennsylvania State University, University Park, PA
A mineral acid (or inorganic acid) is defined as a ...

Handling Chemical Spills

Source: Robert M. Rioux &#38; Taslima Zaman, Pennsylvania State University, University Park, PA
Since chemicals are commonly used for laboratory research ...

Proper Use of Autoclaves

Robert M. Rioux &amp; Zhifeng Chen, Pennsylvania State University, University Park, PA
Autoclaving is one of the most commonly used methods in the ...

Fume Hoods and Laminar Flow Cabinets

Robert M. Rioux &amp; William A. Elliott, Pennsylvania State University, University Park, PA
Fume hoods and laminar flow cabinets are engineering controls ...

handling-air-and-water-sensitive-chemicals-using-a-schlenk-line

Handling Air- and Water-Sensitive Chemicals Using a Schlenk Line

Robert M Rioux, Ajay Sathe, Zhifeng Chen, Pennsylvania State University, University Park, PA
The use of reagents sensitive to oxidation or moisture ...

proper-operation-of-vacuum-based-equipment

Proper Operation of Vacuum Based Equipment

Source: Robert M. Rioux, Ajay Sathe &#38; Zhifeng Chen, Pennsylvania State University, University Park, PA
Vacuum is required for a number of laboratory ...

Operating the Glovebox

Robert M Rioux, Ajay Sathe, Zhifeng Chen, Pennsylvania State University, University Park, PA 
A glovebox is an isolated enclosure that is designed to ...

operation-of-high-pressure-reactor-vessels

Operation of High-pressure Reactor Vessels

Robert M Rioux, Pennsylvania State University, University Park, PA
The use of gases in a synthetic chemistry laboratory is essential for carrying out a ...

CHEM.1.C

Lab Techniques

Measurement Accuracy
The ability to repeat an experiment and get the same results, or reproducibility, is essential in scientific research. However, ...

Scientific Measurement and Lab Skills

Two-Dimensional Graphs
Some chemistry experiments take the form of directly changing one property of the system that you are studying otherwise known as ...

Proper Lab Notebook Keeping

Organic Lab Notebook Keeping
Record keeping is a vital skill in science and organic chemistry labs. Without proper notes, descriptions, quantities, or ...

Glassware in Organic Chemistry
There are standard pieces of glassware that are used in the organic chemistry lab. Beakers and Erlenmeyer flasks are ...

Measurement: Standard Units

Every measurement provides three kinds of information: the size or magnitude of the measurement (a number), a standard of comparison for the measurement ...

Measurement: Derived Units

The International System of Units or SI system, by international agreement, has fixed measurement units for seven fundamental properties: length, mass, ...

uncertainty-in-measurement-accuracy-and-precision

Uncertainty in Measurement: Accuracy and Precision

Scientists typically make repeated measurements of a quantity to ensure the quality of their findings and to evaluate both the precision and the accuracy ...

uncertainty-in-measurement-reading-instruments

Uncertainty in Measurement: Reading Instruments

Counting is the type of measurement that is free from uncertainty, provided the number of objects being counted does not change during the process. Such ...

CHEM.1.E

Scientific and engineering practices. The student, for at least 40% of instructional time, asks questions, identifies problems, and plans and safely conducts classroom, laboratory, and field investigations to answer questions, explain phenomena, or design solutions using appropriate tools and models. The student is expected to:

Organic Lab Glassware and Safe Handling

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