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

Le procedure di laboratorio in chimica organica utilizzano tipicamente attrezzature e tecniche standard per la vetreria. I becher e i palloni di Erlenmeyer sono spesso utilizzati per la semplice miscelazione e tenuta di solventi. I palloni a fondo tondo con collo corto o lungo vengono utilizzati per reazioni ad alto calore o sotto vuoto. Questo perché la forma rotonda è più resistente alle screpolature in queste condizioni.
Le reazioni di riscaldamento sono una procedura di laboratorio comune. Tuttavia, un bruciatore Bunsen non viene generalmente utilizzato per i composti organici perché sono infiammabili. Quando si riscalda una reazione in un becher o in un pallone di Erlenmeyer, in genere viene utilizzata una piastra riscaldante con un agitatore magnetico. Quando si riscalda una reazione in un pallone a fondo tondo, si utilizza un bagnomaria o un mantello riscaldante per adattarsi alla forma del pallone.
Molte reazioni devono essere riscaldate a una certa temperatura per un determinato periodo di tempo per procedere. Queste reazioni vengono eseguite in condizioni di reflusso. Una configurazione a riflusso utilizza un pallone a fondo tondo contenente un solvente il cui punto di ebollizione si sovrappone alla temperatura ottimale della reazione. Un condensatore è montato sul pallone e l'acqua fredda entra dal braccio inferiore ed esce dal braccio superiore. Quando la miscela viene riscaldata e mescolata, il solvente evapora e poi si condensa nuovamente nel pallone, preservando il volume di reazione.
Un'altra tecnica comune utilizzata nel laboratorio di chimica organica è la filtrazione, che è un metodo per separare i solidi dai liquidi. La filtrazione per gravità è la tecnica di filtrazione più semplice utilizzata per separare i solidi insolubili granulari. Questa configurazione è composta da un pallone di Erlenmeyer, un imbuto conico e un pezzo di carta da filtro piegato. La miscela viene versata nell'imbuto e il liquido passa attraverso il pallone, chiamato filtrato. I solidi rimangono sulla carta da filtro.
Una tecnica di filtrazione più veloce è la filtrazione sottovuoto. In questo caso, un imbuto Büchner è collegato a un pallone filtrante tramite un adattatore in gomma. Il pallone filtrante ha l'aspetto di un pallone di Erlenmeyer, ma ha un braccio laterale che collega il pallone al vuoto tramite un tubo del vuoto. Quindi, un pezzo piatto di carta da filtro viene posizionato all'interno dell'imbuto e bagnato leggermente prima che l'aspirapolvere venga acceso lentamente. Il liquido viene aspirato attraverso la carta da filtro nel pallone, mentre il solido viene trattenuto sulla carta da filtro.
 In questo laboratorio, eseguirai una semplice reazione per formare acido benzoico, consentendoti di esercitarti con semplici tecniche di chimica organica, come pesare i solidi, misurare il volume ed eseguire la filtrazione sotto vuoto. Praticherai quindi la tecnica dei riflessi usando il tetraidrofurano.

tecniche di base di chimica organica

Vetreria in Chimica Organica
Ci sono pezzi standard di vetreria che vengono utilizzati nel laboratorio di chimica organica. I becher e i palloni di Erlenmeyer sono tipicamente utilizzati per una semplice miscelazione o per contenere solventi, ma non dovrebbero essere utilizzati per misurare il volume, a meno che non sia necessario solo un volume approssimativo. La vetreria può essere suddivisa nelle seguenti categorie:
<ol>
	<li style="font-size:17px">Vetreria volumetrica - Questo include vetreria come cilindri graduati, pipette di vetro volumetriche e fiasche volumetriche. Lo scopo di questi articoli è quello di misurare o erogare un volume preciso di una sostanza. Un cilindro graduato viene generalmente utilizzato per misurare i volumi in un laboratorio organico. Il cilindro graduato ha una forma cilindrica lunga con marcature di volume sul lato. È essenziale utilizzare il cilindro graduato più piccolo possibile per il volume necessario al fine di ridurre al minimo l'errore. Ad esempio, un cilindro graduato da 25 ml è sufficiente per misurare 20 ml di reagente, ma non è accurato misurare un volume più piccolo, come 5 ml. Tuttavia, non utilizzare un cilindro graduato da 25 ml per misurare 100 ml misurando quattro volumi da 25 ml; è preferibile utilizzare il cilindro graduato da 100 mL.</li>
	<li style="font-size:17px">Contenimento della reazione - Questi pezzi specializzati possono essere utilizzati per ospitare una reazione chimica organica. I palloni a fondo tondo sono un esempio di questa vetreria. A differenza dei matracci di Erlenmeyer, i palloni a fondo tondo offrono una maggiore superficie e quindi un riscaldamento o un raffreddamento più uniforme. I palloni a fondo tondo vengono utilizzati per eseguire reazioni ad alto calore o sotto vuoto perché la loro forma rotonda è più resistente alle fessurazioni. In questa categoria rientrano anche i cristalleria specializzata, nota come condensatori, che viene utilizzata per raccogliere i vapori gassosi e condensarli nuovamente nella fase liquida da raccogliere.</li>
	<li style="font-size:17px">Filtrazione - Questi pezzi di vetro vengono utilizzati principalmente per aiutare a isolare i precipitati da una miscela di reazione. Per isolare i precipitati solidi, è necessario un apparato di filtrazione. La configurazione più semplice utilizza un imbuto di vetro attaccato a un pallone di Erlenmeyer. All'interno dell'imbuto c'è un pezzo di carta da filtro. La miscela di reazione contenente il solido viene versata nell'imbuto e la gravità tirerà il liquido verso il basso nel pallone, lasciando dietro di sé il solido. Questo è noto come filtrazione per gravità. Tuttavia, questa configurazione potrebbe richiedere un lungo periodo di tempo per filtrare il solido. Una configurazione di filtrazione sottovuoto sostituisce il pallone Erlenmeyer con un pallone sottovuoto con un braccio laterale e l'imbuto di vetro con un imbuto filtrante in porcellana noto come imbuto Büchner. Questo braccio laterale è collegato a una fonte di vuoto. Come in precedenza, la miscela di reazione viene versata nell'imbuto filtrante e la filtrazione viene aiutata dalla forza del vuoto.</li>
	<li style="font-size:17px">Separazione - Questi flaconi o imbuti specializzati vengono utilizzati principalmente per le estrazioni in fase liquido-liquido, che è una tecnica che consente la separazione dei prodotti utilizzando solventi con diverse polarità o idrofobicità. Questi liquidi immiscibili formeranno una soluzione eterogenea che si separa in due fasi. Gli imbuti separatori sono dotati di una valvola nota come rubinetto di arresto nella parte inferiore, che consente la separazione delle fasi versandole in un nuovo contenitore.</li>
	<li style="font-size:17px">Trasporto - Questo bicchierino consiste principalmente di bottiglie o fiale con un tappo corrispondente. Questa vetreria viene utilizzata principalmente per il trasporto sicuro di materiale potenzialmente pericoloso.</li>
	<li style="font-size:17px">Uso generale - Questa categoria comprende oggetti in vetro come bicchieri, fiasche di Erlenmeyer, bacchette di vetro e qualsiasi altro pezzo vario.</li>
</ol>
Pesatura di reagenti organici
I reagenti organici possono presentarsi in più forme ed è importante praticare una buona tecnica di laboratorio quando si ottengono questi reagenti per l'uso negli esperimenti. Rivedere sempre la scheda di sicurezza di un reagente per determinare i potenziali pericoli quando si lavora con esso. I reagenti solidi devono essere dosati utilizzando barchette di pesata o carta per pesare e il tipo di bilancia appropriato.
Se è necessaria una misurazione precisa, utilizzare una bilancia analitica. Se si deve utilizzare una grande quantità di reagente, utilizzare una bilancia a carica dall'alto. Posizionare una barca per pesare o una carta per pesare sulla bilancia e premere il pulsante "tara". La funzione di tara annullerà la massa della carta di pesata. Utilizzare sempre le spatole per trasferire i reagenti solidi dall'alimentazione alla navicella di pesatura. Non riutilizzare mai la stessa spatola per reagenti diversi in quanto ciò può contaminare i reagenti di riserva. E non rimettere mai il reagente in eccesso nel flacone di riserva. Invece, scartalo nel modo appropriato come indicato.
Quando si trasferisce il solido nel recipiente appropriato, utilizzare un piccolo imbuto per versare con cura il solido all'interno. Se rimane del solido, utilizzare una piccola quantità di solvente da utilizzare sulla navicella di pesatura e trasferirla nel pallone.
I liquidi organici possono essere misurati utilizzando vetreria volumetrica, come un cilindro graduato. Calcolare il volume del liquido utilizzando la sua densità, quindi tarare il pallone di reazione sulla bilancia. Utilizzare una pipetta o un cilindro graduato per trasferire il volume direttamente nel pallone di reazione. Seguire le linee guida per il tipo specifico di vetreria. Non riutilizzare mai lo stesso pezzo di vetreria per più reagenti e non rimettere mai il reagente in eccesso nei flaconi di riserva liquida. Per liquidi, c
Reazioni organiche riscaldanti
A volte è necessario il calore per consentire una reazione chimica organica. Nell'ambiente generale di laboratorio, il calore viene comunemente applicato utilizzando un bruciatore Bunsen con una fiamma a gas diretta. Nei laboratori di chimica organica, una fiamma libera di un bruciatore Bunsen può creare una situazione pericolosa. I reagenti organici, in particolare i solventi, sono altamente combustibili e alcuni formano vapori con relativa facilità. Per questo motivo, i bruciatori Bunsen non vengono utilizzati nei laboratori di chimica organica.
Invece, bagni di riscaldamento, piastre riscaldanti o mantelli vengono utilizzati per fornire una fonte indiretta di calore. Le piastre riscaldanti con funzione di agitazione magnetica vengono utilizzate per riscaldare becher e matracci di Erlenmeyer. I mantelli riscaldanti sono progettati per riscaldare in sicurezza un pallone a fondo tondo con volumi variabili. I bagni d'acqua vengono utilizzati quando la temperatura della reazione non deve superare i 100 °C. Una reazione nella vetreria viene immersa in un bagno d'acqua riscaldato da una piastra riscaldante. La temperatura è modulata all'intervallo appropriato. Se la temperatura richiesta deve superare i 100 °C ma non i 250 °C, è possibile utilizzare un mantello in silicone. Se la temperatura deve superare i 250 °C, è possibile utilizzare un bagno di sabbia.
Molte reazioni richiedono di essere riscaldate a una certa temperatura per lunghi periodi di tempo affinché procedano. Tuttavia, se una reazione viene riscaldata per un lungo periodo di tempo, il solvente può evaporare, causando una perdita della soluzione di reazione. Invece, viene spesso utilizzata una configurazione a riflusso, che utilizza un pallone a fondo tondo contenente un solvente. Il punto di ebollizione del solvente si sovrappone alla temperatura ottimale della reazione. Il pallone a fondo tondo è fissato a un supporto e un condensatore è montato sul pallone. L'acqua fredda scorre attraverso il condensatore dal braccio inferiore a quello superiore mentre la miscela viene riscaldata e mescolata. Quando la miscela viene riscaldata, il solvente evapora e poi si condensa nuovamente nel pallone, preservando il volume di reazione.

Tecniche di base di chimica organica

Vetreria in Chimica Organica
Ci sono pezzi standard di vetreria che vengono utilizzati nel laboratorio di chimica organica. I bicchieri e i palloni di Erlenmeyer sono ...

Education

Didattica

JoVE Lab Manual

Chimica

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...

scientific measurement and lab skills

Graphs, Curve Fit, and Standard Deviation

Two-dimensional graphs help students compare an independent variable with a dependent variable in science data. In a chemistry example, temperature is the independent variable and volume is the dependent variable. After data are collected, the relationship between the two measurements must be quantified so it can be evaluated and compared with other relationships. A graph can also show when no relationship exists between the two variables. To make a two-dimensional graph, each data point needs...

stoichiometry, product yield, and limiting reactants

stoichiometry-product-yield-and-limiting-reactants

Balancing Equations and Reactant Limits

Chemical equations show how reactants change into products during a reaction. Stoichiometry is the study of the relative amounts of reactants and products. It is based on the Law of Conservation of Mass, which says matter is neither created nor destroyed. Because atoms are only rearranged, the number and identity of atoms must match on both sides of a reaction. That is why a chemical equation must be balanced. A balanced equation has the same number of atoms for each element in the reactants...

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

The ideal gas equation brings together the main gas laws used in chemistry. Gases have molecules that are far apart, so their behavior is described with four measurable variables: pressure, volume, number of moles, and temperature. The ideal gas law links these variables with the gas constant, R, which equals 8.314 J·K−1 mol−1. Boyle’s law describes the link between pressure and volume. When temperature and the number of moles stay constant, pressure and volume change in opposite directions.

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

Reaction heat is explained through enthalpy, Hess’s law, and calorimetry. These ideas show how heat moves during chemical reactions and how scientists measure it. Thermodynamics is the study of heat energy and other forms of energy, such as work. Its laws are used across science, from biology to physics. The first law says energy is conserved in an isolated system. Energy can change form, such as thermal energy becoming work, but it cannot be created or destroyed. The second law of...

solubility

Solubility in Water and Other Solvents

Solubility describes how much of a solute can dissolve in a specific solvent. It is usually reported as solute mass per solvent volume or as solute mass per solvent mass. For example, sodium chloride has a solubility of 36 g per 100 mL of water at room temperature. If solubility is given by solvent mass, that mass must be converted to volume for later calculations. Temperature changes solubility. Sodium carbonate dissolves at about 7 g per 100 mL of water at 0 °C, 22 g per 100 mL at room...

metal flame emission

Flame Test Metal Color Clues

Flame testing uses a metal sample and a flame to identify a substance by its color. Each element gives off a characteristic light emission in the flame, so the color can help distinguish one element from another. This same idea appears in fireworks, where different metal components create different colors. The color comes from energy absorbed by the metallic component. When a species absorbs energy, that energy can go into translation, vibration, rotation, or electron excitement. Electron...

balmer series

Hydrogen Emission Lines

Hydrogen emission lines show how electrons move between fixed energy levels in the Bohr model. Niels Bohr proposed this model for the hydrogen atom in 1913. In this model, an electron can only occupy certain orbits, and it cannot exist between them. These energy states are labeled with the quantum number n. The ground state is n = 1. Higher values, such as n = 2, 3, 4, and so on, are excited states. An electron changes state only by absorbing or emitting energy equal to the difference between...

beer's law

Absorbance Spectra and Beer-Lambert Analysis

Absorbance spectra and the Beer-Lambert Law show how light can be used to study molecules in solution. When light hits a substance, it may be absorbed, transmitted, or reflected. A substance often interacts with a range of wavelengths, and each wavelength can affect the molecules or atoms in a different way. When a molecule absorbs light, that energy can be used for translation, vibration, rotation, or electron excitement. Electron excitement is especially important in spectroscopy because it...

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

Chemical kinetics explains how fast a reaction happens and why that speed changes. The reaction rate is the speed of a chemical reaction. It is defined as the change in concentration of a reactant or product over time. Reaction speed depends on several factors, including the concentration of the reactants and the temperature of the reaction. Each reactant affects the rate in a specific way. That relationship is described by the rate law. The rate law is an equation that connects the...

galvanic cells

Battery Power from Redox Reactions

Electrochemistry studies how chemical change and electrical energy are linked. In this branch of chemistry, electrons move from one species to another. That movement can either produce current or be driven by an applied current. The main reaction in electrochemistry is the oxidation-reduction, or redox, reaction. A redox reaction has two half-reactions. Oxidation is the loss of electrons, and reduction is the gain of electrons. These changes also shift the oxidation state of each substance. The...

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

Triglycerides are lipids made of a glycerol backbone linked to three fatty acids. They are common in vegetable oils and animal fats. Plant lipids are the basis of vegetable oils, while animal lipids are used as lard or general sources of fats. A fatty acid has a long carbon chain, usually between 12 and 20 carbons, with a weak organic acid at one end. Some fatty acids contain double bonds. These are unsaturated fats. The double bond usually gives the chain a bent, cis shape. As a result,...

synthesis of luminol

Luminol Chemiluminescence in Forensics

Luminol chemiluminescence shows how a chemical reaction can produce light and help with blood detection. Chemical reactions may be endothermic or exothermic, depending on whether they absorb or release heat as reactants become products. The enthalpy of a reaction is the energy difference between reactants and products, or ΔH. A positive ΔH means the reaction is endothermic. A negative ΔH means it is exothermic. Many reactions do not happen in a single step. They can pass through intermediates...

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

Video completi e incentrati sul curriculum sia per gli istruttori che per gli studenti nei corsi di laboratorio di Chimica introduttiva.

https://cloudfront.jove.com/files/banners/scicat/labbio.jpg

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

Preparati a insegnare Tecniche di base di chimica organica con questa guida per istruttori di 3 minuti. Copre i passaggi chiave di preparazione per il laboratorio Chemistry su JoVE Lab Manual.

Preparazione dell'istruttore per Tecniche di base di chimica organica in Chemistry - Oltre 4.4K visualizzazioni | JoVE Lab Manual

Segui le procedure passo dopo passo di Tecniche di base di chimica organica in questo video di protocollo studente di 16 minuti. Parte della collezione Chemistry su JoVE Lab Manual.

Protocollo studente per Tecniche di base di chimica organica in Chemistry - Oltre 30K visualizzazioni | JoVE Lab Manual

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

Description

Transcript

Tags

More videos by Standards