Name: carbonyl tests for aldehydes and ketones
Uploaded: 2020-03-26T07:22:29.000Z
Duration: 3 min 9 s
Channel: JoVE

K12 Standards

Florida Department of Education

High School

Physical Science

SC.912.P.8

SC.912.P.8.13

identification-of-unknown-aldehydes-and-ketones

Identification of Unknown Aldehydes and Ketones

Aldehydes and ketones have a similar structure. Both possess a carbonyl group, which is a carbon double bonded to an oxygen. An aldehyde has at least one hydrogen connected to the carbonyl carbon. The second group is either a hydrogen or a carbon-based group. In contrast, a ketone has two carbon-based groups connected to the carbonyl carbon. Certain reactions undergone by aldehydes and ketones can be used to distinguish them or identify their functional groups based on visible differences in the reaction&#39;s outcome.
One such reaction is the DNPH test, which is used to determine whether an aldehyde or ketone is aromatic. In this reaction, 2,4-dinitrophenylhydrazine, or DNPH, attacks the carbonyl of an aldehyde or ketone in an aqueous acidic solution. This condensation reaction produces a hydrazone, which precipitates from the aqueous solution.
When a non-aromatic ketone or aldehyde reacts with DNPH, the precipitate is yellow. However, aromatic ketones and aldehydes give a red-orange precipitate. DNPH can also be used to distinguish alcohols and esters from aldehydes and ketones since DNPH does not react with alcohols or esters. We call this lack of reaction a negative result.
Another useful reaction is used as the iodoform test for methyl ketones, which are ketones that have at least one methyl as a functional group. When a methyl ketone is mixed with iodine under aqueous alkaline conditions, iodine replaces each methyl hydrogen, making an excellent leaving group. Substitution, followed by proton transfer, converts the leaving group into iodoform, which precipitates from the solution as a pale yellow solid.
This reaction also works for acetaldehyde, which is an aldehyde with methyl as its R group. The reaction relies on the unique reactivity of the hydrogens in an alpha-methyl group, so mixing any other ketone or aldehyde with iodine will not make solid yellow iodoform.
Finally, we can distinguish between ketones and aldehydes using the Tollens test. Diamminesilver(1+), or Tollens&#39; reagent, oxidizes aldehydes to carboxylic acids. Tollens&#39; reagent is reduced to elemental silver in the process, which either coats the inner wall of the test tube or forms a black precipitate. Most ketones, however, are not oxidized by Tollens&#39; reagent, so no solid silver will form.
In this lab, you will identify several unknown aldehydes and ketones by performing the DNPH test, the Tollens test, and the iodoform test.

identification of unknown aldehydes and ketones

<h4>Aldehydes and Ketones</h4>
Aldehydes and ketones have a carbonyl group (C=O) as a functional group. A ketone has two alkyl or aryl groups attached to the carbonyl carbon (RCOR&#8217;). The simplest ketone is acetone, which has two methyl groups attached to the carbonyl carbon (CH3COCH3).
An aldehyde is similar to a ketone, except that instead of two side groups connected to the carbonyl carbon, they have at least one hydrogen (RCOH). The simplest aldehyde is formaldehyde (HCOH), as it has two hydrogens connected to the carbonyl group. All other aldehydes have one hydrogen bonded to the carbonyl group, like the simple molecule acetaldehyde, which has one hydrogen and one methyl group (HCOCH3).
The carbonyl carbon in both aldehydes and ketones is electrophilic, meaning that it has a dipole due to the electronegativity of the attached oxygen atom. This makes the carbonyl carbon an ideal target for nucleophiles in a nucleophilic addition reaction. During this reaction, the nucleophile, or electron donor, attacks the carbonyl to form the tetrahedral intermediate. The negatively charged oxygen accepts a hydrogen ion to form a hydroxyl group.
Typically, nucleophiles possess a negative charge or lone pair on a heteroatom, which can take several forms (OH-, RO-, CN-, R3C-, RNH2, ROH). For primary amines (RNH2), the reaction does not stop at the formation of the tetrahedral intermediate with a hydroxyl group. Rather, an elimination reaction occurs that produces a double-bonded carbon and nitrogen functional group known as an imine. Understanding the reactions that aldehydes and ketones can undergo provides a way to differentiate between these similar organic compound types.
<h4>DNPH Test</h4>
The formation of imines from ketones or aldehydes is exploited through the use of the reagent 2,4-dinitrophenylhydrazine (DNPH). In this addition-elimination reaction, the primary amino group of the DNPH attacks the carbonyl of an aldehyde or ketone in an acidic environment. The condensation reaction results in the formation of a hydrazone, which precipitates out of solution.
Precipitates that are yellow indicate non-conjugated ketones or aldehydes, whereas red-orange precipitates indicate conjugated systems. This test is used to differentiate ketones and aldehydes from alcohols and esters with which DNPH does not react, and thus no precipitate is formed. The ketone or aldehyde derivatives are crystalline materials with very well-defined melting points, which are reported in the literature and can be used to identify the specific compounds.
<h4>Haloform Test</h4>
Another test is the haloform test, which is used to determine whether a ketone is a methyl ketone. Methyl ketones have a methyl group connected to the carbonyl carbon (RCOCH3). The R group can be either a hydrogen (methyl aldehyde), an alkyl group, or an aryl group.
The reaction mechanism for the haloform test occurs under basic conditions. First, the ketone undergoes a keto-enol tautomerization. Then the nucleophilic enolate attacks the iodine to give an iodine ion and a halogenated ketone. This repeats a total of three times until all hydrogens of the ketone methyl group are replaced by an iodine. Next, the hydroxide reacts with the electrophilic carbonyl carbon center to form the tetrahedral intermediate with a negatively-charged oxygen, which is single bonded to the carbonyl. Upon reformation of the C-O double bond, the trihalomethyl group leaves as a stabilized leaving group. Lastly, the formed carboxylic acid is deprotonated by the negativelycharged trihalomethyl goup to give the haloform &#8212; trihalomethane &#8212; and a carboxylate. If iodine is the halogen, the precipitate will have a characteristic yellow color. This reaction will only occur for methyl ketones, and it will give a negative result for any other carbonyl-containing compound.
<h4>Tollens Test</h4>
The Tollens&#8217; test is a reaction that is used to distinguish aldehydes from ketones, as aldehydes are able to be oxidized into a carboxylic acid while ketones cannot. Tollens&#8217; reagent, which is a mixture of silver nitrate and ammonia, oxidizes the aldehyde to a carboxylic acid. The silver ion Ag+ is reduced to solid silver, Ag(s). The solid silver forms a film on the inner wall of the test tube, resembling a silver mirror. Ketones do not react with Tollen&#8217;s reagent, and therefore do not result in the formation of a silver mirror on the walls of the test tube.
<h4>References</h4>
<ol>
	<li style="font-size:17px">Streitwieser, A., Heathcock, C.H., Kosower, E.M. (1998). Introduction to Organic Chemistry. Upper Saddle River, NJ: Prentice Hall.</li>
	<li style="font-size:17px">Fuson, R.C., Bull, B.A. (1934). The Haloform Reaction. Chemical Reviews. 15(3), 275-309.</li>
</ol>

Aldehydes and Ketones
Aldehydes and ketones have a carbonyl group (C=O) as a functional group. A ketone has two alkyl or aryl groups attached to the ...

Education

JoVE Lab Manual

Chemistry

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 pulls electron density toward itself. This makes the carbonyl carbon a target for nucleophiles, or electron donors, in a nucleophilic addition reaction. In that reaction, the nucleophile attacks the carbonyl and forms a tetrahedral intermediate. The negatively charged oxygen then accepts a hydrogen ion to form a hydroxyl group. Common nucleophiles can include OH-, RO-, CN-, R3C-, RNH2, and ROH. With primary amines, the reaction continues past the intermediate and can form an imine, which has a carbon-nitrogen double bond.

These reaction patterns help chemists tell similar carbonyl compounds apart. One useful test is the 2,4-dinitrophenylhydrazine, or DNPH, test. In acidic solution, DNPH reacts with an aldehyde or ketone by an addition-elimination process. The result is a hydrazone precipitate. Yellow precipitates usually point to non-conjugated aldehydes or ketones, while red-orange precipitates suggest conjugated systems. Alcohols and esters do not react with DNPH, so no precipitate forms. The crystalline derivatives also have well-defined melting points that can help identify the specific compound.

Another test is the haloform test, which checks whether a ketone is a methyl ketone. A methyl ketone has a methyl group attached to the carbonyl carbon, written as RCOCH3. In basic conditions, the ketone first undergoes keto-enol tautomerization. Then the enolate reacts with iodine until the methyl hydrogens are replaced. After three substitutions, hydroxide reacts again, and the trihalomethyl group leaves. The reaction gives a haloform, which is a trihalomethane, along with a carboxylate. When iodine is used, the precipitate is yellow. This test is negative for carbonyl compounds that are not methyl ketones.

The Tollens test distinguishes aldehydes from ketones. Tollens reagent is a mixture of silver nitrate and ammonia. It oxidizes an aldehyde to a carboxylic acid, while silver ion, Ag+, is reduced to solid silver, Ag(s). The silver coats the inside of the test tube and forms a silver mirror. Ketones do not react with Tollens reagent, so they do not produce this mirror.

Carbonyl Tests for Aldehydes and Ketones

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 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...

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...

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

Comprehensive, curriculum-focused videos for both instructors and students in introductory chemistry lab courses.

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

Learn how DNPH, haloform, and Tollens tests help identify aldehydes and ketones by spotting precipitates, methyl ketones, and the silver mirror.

Carbonyl Tests for Aldehydes and Ketones | JoVE K12

Georgia Standards of Excellence

9-12

SC3.

Indicators of Chemical Reactions

Learn how to prepare DNPH, iodoform, and Tollens' reagents and set up a high school lab for testing unknown aldehydes and ketones.

Preparing Reagents for Aldehyde and Ketone Tests | JoVE K12

Use DNPH, Tollens’ reagent, and the iodoform test to identify unknown aldehydes and ketones, compare results with known samples, and match hydrazone melting points.

Aldehyde and Ketone Spot Tests | JoVE K12

Classifying Matter by State

Chemistry is the study of matter and the changes it undergoes. Matter is anything that has mass and occupies space. Matter is all around us; the air, ...

States of Matter

Solids, liquids, and gases are the three states of matter commonly found on Earth. A solid is rigid and possesses a definite shape. A liquid flows and ...

States of Matter and Phase Changes

The internal energy of a substance&#8212;the total kinetic energy of all its molecules and the potential energy of their associated forces&#8212;depends ...

molecular-comparison-of-gases-liquids-and-solids

Molecular Comparison of Gases, Liquids, and Solids

Particles in a solid are tightly packed together (fixed shape) and often arranged in a regular pattern; in a liquid, they are close together with no ...

Differentiate between physical and chemical properties and physical and chemical changes of matter.

SC.912.P.8.1

physical-and-chemical-properties-of-matter

Physical and Chemical Properties of Matter

The characteristics that enable us to distinguish one substance from another are called properties.

Physical Properties of Matter

A physical property is ...

Phase Transitions

Whether solid, liquid, or gas, a substance&#39;s state depends on the order and arrangement of its particles (atoms, molecules, or ions). Particles in the ...

phase-transitions-vaporization-and-condensation

Phase Transitions: Vaporization and Condensation

The physical form of a substance changes on changing its temperature. For example, raising the temperature of a liquid causes the liquid to vaporize ...

Vapor Pressure

When a liquid vaporizes in a closed container, gas molecules cannot escape. As these gas phase molecules move randomly about, they will occasionally ...

Clausius-Clapeyron Equation

The equilibrium between a liquid and its vapor depends on the temperature of the system; a rise in temperature causes a corresponding rise in the vapor ...

Phase Transitions: Melting and Freezing

Heating a crystalline solid increases the average energy of its atoms, molecules, or ions, and the solid gets hotter. At some point, the added energy ...

phase-transitions-sublimation-and-deposition

Phase Transitions: Sublimation and Deposition

Some solids can transition directly into the gaseous state, bypassing the liquid state, via a process known as sublimation. At room temperature and ...

Heating and Cooling Curves

When a substance&#8212;isolated from its environment&#8212;is subjected to heat changes, corresponding changes in temperature and phase of the substance ...

Phase Diagrams

A phase diagram combines plots of pressure versus temperature for the liquid-gas, solid-liquid, and solid-gas phase-transition equilibria of a substance. ...

SC.912.P.8.2

The Atomic Theory of Matter

The earliest recorded discussion of the basic structure of matter comes from ancient Greek philosophers. Leucippus and Democritus argued that all matter ...

Subatomic Particles

Dalton was only partially correct about the particles that make up matter. All matter is composed of atoms, and atoms are composed of three smaller ...

The Wave Nature of Light

The nature of light has been a subject of inquiry since antiquity. In the seventeenth century, Isaac Newton performed experiments with lenses and prisms ...

The Electromagnetic Spectrum

The electromagnetic spectrum consists of all the types of electromagnetic radiation arranged according to their frequency and wavelength. Each of the ...

Interference and Diffraction

Interference is a characteristic phenomenon exhibited by waves. When two electromagnetic waves interact with their peaks and troughs coinciding, a ...

Photoelectric Effect

When light of a particular wavelength strikes a metal surface, electrons are emitted. This is called the photoelectric effect. The minimum frequency of ...

The Bohr Model

Following the work of Ernest Rutherford and his colleagues in the early twentieth century, the picture of atoms consisting of tiny dense nuclei surrounded ...

Emission Spectra

When solids, liquids, or condensed gases are heated sufficiently, they radiate some of the excess energy as light. Photons produced in this manner have a ...

The de Broglie Wavelength

In the macroscopic world, objects that are large enough to be seen by the naked eye follow the rules of classical physics. A billiard ball moving on a ...

The Uncertainty Principle

Werner Heisenberg considered the limits of how accurately one can measure properties of an electron or other microscopic particles. He determined that ...

The Quantum-Mechanical Model of an Atom

Shortly after de Broglie published his ideas that the electron in a hydrogen atom could be better thought of as being a circular standing wave instead of ...

Explore the scientific theory of atoms (also known as atomic theory) by describing changes in the atomic model over time and why those changes were necessitated by experimental evidence.

SC.912.P.8.3

Elements: Chemical Symbols and Isotopes

A chemical symbol is an abbreviation used to indicate an element or an atom of an element. For example, the symbol for mercury is Hg. The same symbol is ...

Ions and Ionic Charges

In ordinary chemical reactions, the nucleus &mdash; which contains the protons and neutrons of each atom and thus identifies the element &mdash; remains ...

The Periodic Table

As early chemists discovered more elements, they realized that various elements could be grouped by their similar chemical behaviors. One such grouping ...

Atomic Mass

Atoms &mdash; and the protons, neutrons, and electrons that compose them &mdash; are extremely small. For example, a carbon atom weighs less than 2 ...

Atomic Number and Mass Number

The number of protons in the nucleus of an atom is its atomic number (Z). This is the defining trait of an element. Its value determines the identity of ...

Explore the scientific theory of atoms (also known as atomic theory) by describing the structure of atoms in terms of protons, neutrons and electrons, and differentiate among these particles in terms of their mass, electrical charges and locations within the atom.

SC.912.P.8.4

Periodic Classification of the Elements

The periodic table arranges atoms based on increasing atomic number so that elements with the same chemical properties recur periodically. When their ...

Electron Configurations

Electron configurations and orbital diagrams can be determined by applying the Aufbau principle (each added electron occupies the subshell of lowest ...

Electronic Structure of Atoms


An atom comprises protons and neutrons, which are contained inside the dense, central&#160;core called the nucleus, with electrons present around the ...

Relate properties of atoms and their position in the periodic table to the arrangement of their electrons.

SC.912.P.8.5

A. A working definition of matter is that it takes up space, has mass, and has measurable properties. Matter is comprised of atomic, subatomic, and elementary particles.

B. Electrons are key to defining chemical and some physical properties, reactivity, and molecular structures. Repeating (periodic) patterns of physical and chemical properties occur among elements that define groups of elements with similar properties. The periodic table displays the repeating patterns, which are related to the atom's outermost electrons. Atoms bond with each other to form compounds.

C. In a chemical reaction, one or more reactants are transformed into one or more new products. Many factors shape the nature of products and the rates of reaction. 

D. Carbon-based compounds are building-blocks of known life forms on earth and numerous useful natural and synthetic products.

Carbonyl Tests for Aldehydes and Ketones

Description

Transcript

Tags

More videos by Standards