Name: absorbance spectra and beer-lambert analysis
Uploaded: 2020-03-26T07:22:26.000Z
Duration: 2 min 53 s
Channel: JoVE

K12 Standards

Texas Essential Knowledge and Skills

High School

Chemistry and Physics

IPC.7

IPC.7.E

Beer's Law

Birçok kimyasal reaksiyon ileri ve geri olmak üzere iki yönde ilerler. Zamanla, ileri ve geri reaksiyonlar aynı oranda gerçekleşecek ve reaktanların ve ürünlerin konsantrasyonu artık değişmeyecektir. Bu kimyasal denge olarak bilinir.
Kimyasal dengede, her bir bileşenin konsantrasyonları, her biri stokiyometrik katsayılarının gücüne yükseltilen, ürün konsantrasyonlarının reaktan konsantrasyonlarına oranı olan denge sabiti K ile birbiriyle ilişkilidir.
Ancak denge konsantrasyonlarını nasıl belirlersiniz? Bir yöntem, ürünün bir numuneden geçmeden önce ve sonra emdiği bir dalga boyunun yoğunluğunu ölçer. Yoğunluk farkına absorbans denir ve numunedeki absorbe edici bileşiğin miktarına karşılık gelir.
Elektronların çoğunlukla temel durumu işgal ettiğini hatırlayabilirsiniz. Belli bir miktarda enerji emdiklerinde, daha yüksek bir enerji seviyesine uyarılırlar. Bu enerji, belirli bir ışık dalga boyuna karşılık gelir. Bu dalga boyunu bulabilir ve bir ışık demetini numuneden geçiren ve bir veya daha fazla dalga boyunda yoğunluktaki değişimi ölçen bir spektrofotometre ile absorbasyonu ölçebilirsiniz.
Soğurma, gelen ışığın yoğunluğu üzerindeki zayıflatılmış ışığın yoğunluğunun negatif günlüğüne eşittir. Bilinen farklı ürün konsantrasyonlarına sahip birden fazla çözeltinin absorbans değerlerini çizerek, absorbans ve konsantrasyon arasında doğrusal bir ilişki gözlemliyoruz. Bu Beer Yasasının bir örneğidir.
Bira Yasası bu denklemle matematiksel olarak ifade edilir, burada A absorbans, epsilon molar zayıflama katsayısı, her bileşik için değişen bir sabit, l numune boyunca ışığın yol uzunluğu ve c bileşiğin konsantrasyonudur.
Belirli bir dalga boyunda ve yol uzunluğunda belirli bir bileşik için doğrusal fonksiyonu tanımlayarak, ürünün denge konsantrasyonunu belirlemek için dengedeki bir çözeltinin absorbans verilerini kullanabilirsiniz. Oradan, reaktanların denge konsantrasyonlarını hesaplayabilir ve denge sabitini çözebilirsiniz. Bu laboratuvarda, demir(III) izotiyosiyanat çözeltileri hazırlayacak ve çeşitli konsantrasyonlarda absorbansını belirlemek için bir spektrofotometre kullanacaksınız.

bira yasası

Absorbans ve Floresan
Işık bir maddeye çarptığında ya emilir, iletilir ya da yansıtılır. Tipik olarak, bir madde, her biri moleküller veya atomlarla farklı şekilde etkileşime giren bir dizi dalga boyu ile etkileşime girer. Bir madde belirli bir dalga boyu aralığını emebilir, başka bir dalga boyu aralığını yansıtabilir ve diğer dalga boylarını iletebilir.
Bir molekül ışığı emdiğinde, enerji dört farklı şekilde kullanılır: (1) molekülün moleküler hızını değiştirmesine neden olan translasyon; (2) moleküller arasındaki mesafenin hızla değişmesine neden olan titreşim; (3) atomların bir moleküldeki bağlar etrafında dönmesine neden olan rotasyon; ve (4) elektronların daha yüksek enerji seviyelerine geçmesine neden olan elektron uyarımı.
<h4>Enerji Seviyeleri</h4>
1913'te Niels Bohr, elektronların durağan durumlar adı verilen sabit, dairesel yörüngelerde çekirdeğin etrafında hareket ettiği hidrojen atomu için bir model önerdi. Her yörünge veya durağan durumla ilişkili enerji, yalnızca sabit, ayrık enerjilerde bulunur. Sadece bir elektron başka bir yörüngeye hareket ettiğinde enerji emilir veya yayılır. Elektron hiçbir zaman ara durumlar arasında değildir. Bu değişiklik, yalnızca emilen veya yayılan enerji, iki enerji durumu arasındaki farka eşitse meydana gelir.
Bohr'un modelinde, n kuantum sayısı elektronun enerjisini temsil eder. Bir elektron mümkün olan en düşük enerji durumunu işgal ettiğinde, n = 1 olan temel durumu işgal ettiği söylenir. Bir elektron, enerjisi birinci ve ikinci durumlar arasındaki farka eşit olan bir fotonu emdiğinde, elektron uyarılır ve temel durumdan uyarılmış duruma geçer, burada n = 2. Fotonun enerjisi birinci ve üçüncü durumlar arasındaki farka eşitse, elektron üçüncü duruma geçer veya n = 3 vb.
Elektronlar kendiliğinden temel duruma veya başka herhangi bir düşük, uyarılmış duruma geri dönebilir. Bu olduğunda, uyarmadan elde edilen fazla enerji, yayılan bir foton şeklinde salınır. Fotonun enerjisi, iki enerji durumu arasındaki farka eşittir ve ışığın farklı dalga boylarına karşılık gelir.
<h4>Absorpsiyon ve Emisyon Spektrumları</h4>
Çoğu madde bir dalga boyunda maksimum miktarda ışığı emer veya yayarken, aynı zamanda bir dalga boyu aralığında ışığı emme veya yayma eğilimindedirler. Bu dalga boyu aralığına spektrum denir. Emilen ışığın enerjisi, bir absorpsiyon spektrumu kullanılarak ölçülür ve görselleştirilirken, yayılan ışığın enerjisi bir emisyon spektrumu kullanılarak ölçülür ve görselleştirilir.
Absorpsiyon ve emisyon spektrumları, ışığı bir numuneden geçiren ve ardından içinden geçen ışığın hem dalga boyunu hem de yoğunluğunu ölçen bir cihaz olan bir spektrofotometre kullanılarak ölçülür. Spektrofotometrenin içinde, gelen ışığı bileşen dalga boylarına ayıran bir kırınım ızgarası veya bir prizma bulunur. Farklı dalga boyları daha sonra numune boyunca iletilir ve yoğunluk, doğrusal bir yük bağlantılı cihaz (CCD) dedektörüne kaydedilir. CCD, piksel adı verilen ışığa duyarlı elemanlar oluşturan silikon bir yüzeye kazınmış entegre bir devredir. CCD, kırınıma uğrayan ışığı toplar ve sıralar ve bir soğurma dalga boyunda geri okur.
Bir numunenin absorbansını ölçerken, çözünen madde genellikle bir çözücü içinde çözülür ve küvet olarak bilinen bir kaba yerleştirilir. Daha sonra numune spektrofotometrenin içine yerleştirilir ve iletilen ışığın yoğunluğu, bir absorbans spektrumu elde etmek için ışığın dalga boyları ile birlikte ölçülür. Beklendiği gibi, iletilen ışığın yoğunluğu, spektrofotometrenin içinde örnek bulunmadığı duruma göre daha düşüktür.
Bunun nedeni, iletilen ışığın numune, küvet ve çözücü tarafından emilmesidir. Numuneleri ölçmeden önce, spektrofotometre bir 'boş' ile kalibre edilmelidir. Boş, yalnızca çözünen maddeyi çözmek için kullanılan çözücüyü içeren bir küvettir. Spektrofotometre, küvet ve çözücüden kaynaklanan toplam absorbans, numunenin ölçülen absorbansından çıkarılacak şekilde kalibre edilir. Bu, yalnızca ilgilenilen türe atfedilen emilimi kaydetmemizi sağlar.
Absorbans genellikle bir dalga boyunda, maksimum absorbans dalga boyunda ölçülür. Bununla birlikte, absorpsiyon, absorpsiyon spektrumunu elde etmek için bir dizi dalga boyunda da ölçülebilir. Bunun için numune, gelen ışığın bir dizi dalga boyuna maruz bırakılır ve absorpsiyon her dalga boyunda kaydedilir. Numune ışık yayarsa, gelen dalga boyunun maksimum absorbans dalga boyunda sabitlenmesi dışında, emisyon spektrumu benzer şekilde ölçülür. Cihaz daha sonra bir dizi dalga boyunda yayılan ışığın yoğunluğunu ölçer.
<h4>Beer-Lambert Yasası</h4>
Bir numunenin maksimum absorbans dalga boyunda absorbans yapması, numune hakkında bilgi verir, yani konsantrasyonu hakkında bilgi verir. Beer-Lambert Yasası, geçirgenliği numune konsantrasyonu ile ilişkilendiren bir denklemdir. İletilen ışığın geçirgenliği veya yoğunluğu, numuneden geçen orijinal ışığın (I) gelen ışığın yoğunluğuna (I0) bölünmesiyle elde edilir.
<img src="/CDNSource/lm/labs/49/49_Concepts_1.jpg" alt="Geçirgenlik denklemi \(T = \frac{I}{I_0}\), optik yoğunluk analizi diyagramı." data-altupdatedat="1754907201000">
Beer-Lambert Yasası, çözeltideki bir türün optik absorpsiyonunun, A'nın, geçirgenliğin negatif kütüğü ile ilişkili olduğunu belirtir.
<img src="/CDNSource/lm/labs/49/49_Concepts_2.jpg" alt="Absorbans formülü A=-log(T), spektroskopi çalışmalarında optik absorpsiyon analizi denklemi." data-altupdatedat="1754907201000">
Beer-Lambert Yasasının alternatif bir versiyonu, çözeltideki bir türün optik absorpsiyonunun, A'nın, dalga boyu, λ ve yol uzunluğu, l sabit tutulduğunda, o türün konsantrasyonu, c ile doğrusal olarak orantılı olduğunu belirtir.
<img src="/CDNSource/lm/labs/49/49_Concepts_3.jpg" alt="Beer-Lambert Yasası denklemi, A=εcl, absorpsiyon kavramı, spektroskopik veri analizi, fizik diyagramı." data-altupdatedat="1754907201000">
Molar zayıflama katsayısı ε, bir türün belirli bir dalga boyunda ışığı ne kadar güçlü emdiğinin bir ölçüsüdür. Molar zayıflama katsayısı ne kadar büyükse, absorbans o kadar büyük olur. Yol uzunluğu, l, küvetin genişliği olan ışığın numune boyunca kat ettiği mesafedir. Standart küvetlerin yol uzunluğu 1 cm'dir.
Absorbans ve konsantrasyon arasındaki bu doğrusal ilişki, absorbansına dayalı olarak bilinmeyen bir numunenin konsantrasyonunu belirlemek için kullanılan güçlü bir araçtır. Bunu yapmak için, çözünen maddenin bilinen konsantrasyonlarının bir gradyanı kullanılarak standart bir eğri oluşturulur. En yüksek absorbans dalga boyundaki absorbans, λmax, her konsantrasyon için ölçülür.
Konsantrasyona karşı absorbans çizilerek, Beer-Lambert denklemine karşılık gelen doğrusal bir ilişki gözlenir. Bu çizginin eğimi, yol uzunluğunun ve molar zayıflama katsayısının çarpımına eşittir. Bu hesaplanan doğrusal fonksiyon kullanılarak, bilinmeyen numunenin absorbansı biliniyorsa, konsantrasyon kolayca belirlenebilir.
Analiz edilen numune dengede bir reaksiyon ise, absorbans o ürüne veya reaktana özgü λmaks olarak ölçülürse, bir ürünün veya reaktanın denge konsantrasyonunu belirlemek için Beer Yasası kullanılabilir. Konsantrasyon bilindikten sonra, kalan reaktanların ve ürünlerin denge konsantrasyonlarını belirleyebilir ve ardından denge sabiti Keq'yi çözebilirsiniz.
<h4>Başvuru</h4>
<ol>
	<li style="font-size:17px">Kotz, J.C., Treichel Jr, P.M., Townsend, J.R. (2012). Kimya ve Kimyasal Reaktivite. Belmont, CA: Brooks/Cole, Cengage Öğrenme.</li>
	<li style="font-size:17px">Silderberg, M.S. (2009). Kimya: Maddenin ve Değişimin Moleküler Doğası. Boston, MA: McGraw Tepesi, Boston.</li>
	<li style="font-size:17px">Harris, D.C. (2015). Kantitatif Kimyasal Analiz. New York, NY: W.H. Freeman ve Şirketi.</li>
</ol>

Bira Yasası

Absorbans ve Floresan
Işık bir maddeye çarptığında ya emilir, iletilir ya da yansıtılır. Tipik olarak, bir madde bir dizi ile etkileşime girer ...

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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 moves an electron to a higher energy level. In Niels Bohr’s model, electrons in the hydrogen atom move in fixed circular orbits called stationary states, and each state has a discrete energy. An electron can move only when it absorbs or emits energy equal to the difference between two states.

The lowest energy state is the ground state, or n = 1. If a photon has the right energy, the electron can move to a higher state such as n = 2 or n = 3. When the electron returns to a lower state, it releases the extra energy as an emitted photon. The photon energy matches the energy gap between the two states and corresponds to specific wavelengths of light.

Most substances absorb or emit most strongly at one wavelength, but they usually interact with a range of wavelengths. That range is called a spectrum. An absorption spectrum shows how much light a sample absorbs at different wavelengths, and an emission spectrum shows the light a sample gives off. These spectra are measured with a spectrophotometer, which sends light through a sample and records the wavelength and intensity of the light that passes through.

Inside the spectrophotometer, a diffraction grating or a prism separates incoming light into its component wavelengths. The light then passes through the sample, and a linear charge-coupled device, or CCD, detector records the intensity. A CCD is an integrated circuit on silicon that contains light-sensitive pixels. It collects and sorts the diffracted light and reads it back at an absorption wavelength.

For absorbance measurements, the solute is usually dissolved in a solvent and placed in a cuvette, which is the container used in the instrument. The sample is then placed in the spectrophotometer, and the intensity of transmitted light is measured along with wavelength to produce an absorbance spectrum. The transmitted light is lower than when no sample is present because light is absorbed by the sample, the cuvette, and the solvent. Before samples are measured, the spectrophotometer is calibrated with a blank, which is a cuvette that contains only the solvent. This step removes the absorbance from the cuvette and solvent so the reading reflects only the species of interest.

Absorbance is often measured at the wavelength of maximum absorbance, but it can also be recorded across a range of wavelengths. For emission spectra, the incident wavelength is fixed at the wavelength of maximum absorbance, and the instrument measures emitted light over a range of wavelengths. The Beer-Lambert Law then connects absorbance to sample concentration. Transmittance is the fraction of light that passes through the sample, I divided by I0, and absorbance is related to the negative log of transmittance.

A second form of the Beer-Lambert Law shows that absorbance is directly proportional to concentration when wavelength and pathlength stay constant. The molar attenuation coefficient, ε, describes how strongly a species absorbs light at a given wavelength. The pathlength, l, is the distance the light travels through the sample, which is the width of the cuvette. Standard cuvettes have a 1 cm pathlength. This linear relationship makes it possible to find the concentration of an unknown sample from its absorbance.

To do that, a standard curve is made with known concentrations of the solute. The absorbance at λ max is measured for each standard, and the results are plotted as concentration versus absorbance. The line that appears matches the Beer-Lambert equation, and its slope equals the product of the pathlength and the molar attenuation coefficient. Once that line is known, the concentration of an unknown sample can be calculated from its absorbance.

Beer’s Law can also be used for reactions at equilibrium. If absorbance is measured at the λ max of a specific product or reactant, the equilibrium concentration of that species can be found. The concentrations of the other reactants and products can then be determined, and the equilibrium constant K eq can be solved.

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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

Kimya laboratuvar temelleri için, hem eğitmenlere hem de öğrencilere yönelik, kapsamlı ve müfredat odaklı vidolar.

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Explore how spectrophotometers measure absorbance spectra, how blank calibration works, and how Beer-Lambert Law is used to find concentration and equilibrium values.

Absorbance Spectra and Beer-Lambert Analysis | JoVE K12

Louisiana Student Standards for Science

motion-and-stability-forces-and-interactions

Motion And Stability: Forces And Interactions

HS-PS2-6

Bira Yasası öğretimine bu 7 dakikalık eğitmen rehberiyle hazırlanın. JoVE Lab Manual üzerindeki Chemistry laboratuvarı için temel hazırlık adımlarını kapsar.

Chemistry içinde Bira Yasası Eğitmen Hazırlığı - 4.7K+ Görüntülenme | JoVE Lab Manual

17 dakikalık bu öğrenci protokol videosunda Bira Yasası prosedürlerini adım adım takip edin. JoVE Lab Manual üzerindeki Chemistry koleksiyonunun bir parçasıdır.

Chemistry içinde Bira Yasası Öğrenci Protokolü - 40K+ Görüntülenme | JoVE Lab Manual

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 ...

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 ...

Molar Mass

The identity of a substance is defined not only by the types of atoms or ions it contains but by the quantity of each type of atom or ion. For example, ...

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 ...

Types of Chemical Bonds

Chemical bonding theories were pioneered by American chemist Gilbert&#xA0;N. Lewis. He developed a model called the Lewis model to explain the type and ...

Ionic Bonding and Electron Transfer

Ions are atoms or molecules bearing an electrical charge. A cation (a positive ion) forms when a neutral atom loses one or more electrons from its valence ...

The Born-Haber Cycle

Lattice Energy&#xA0;

An ionic compound is stable because of the electrostatic attraction between its positive and negative ions. The lattice energy of a ...

trends-in-lattice-energy-ion-size-and-charge

Trends in Lattice Energy: Ion Size and Charge

An ionic compound is stable because of the electrostatic attraction between its positive and negative ions. The lattice energy of a compound is a measure ...

Covalent Bonding and Lewis Structures

Compared to ionic bonds, which results from the transfer of electrons between metallic and nonmetallic atoms, covalent bonds result from the mutual ...

Electronegativity

Whether a bond is nonpolar or polar covalent is determined by a property of the bonding atoms called electronegativity.&#xA0;

Electronegativity values of ...

bond-polarity-dipole-moment-and-percent-ionic-character

Bond Polarity, Dipole Moment, and Percent Ionic Character

Bond Polarity

The absolute value of the difference in electronegativity (&Delta;EN) of two bonded atoms provides a rough measure of the polarity to be ...

lewis-structures-of-molecular-compounds-and-polyatomic-ions

Lewis Structures of Molecular Compounds and Polyatomic Ions

To draw Lewis structures for complicated molecules and molecular ions, it is helpful to follow a step-by-step procedure as outlined:


	Determine the ...

Bond Energies and Bond Lengths

Stable molecules exist because covalent bonds hold the atoms together. The strength of a covalent bond is measured by the energy required to break it, ...

Bonding in Metals

Metallic bonds are formed between two metal atoms. A simplified model to describe metallic bonding has been developed by Paul Dr&#xFC;de called the ...

Model basic atomic structure and relate an element's atomic structure to its bonding, reactivity, and placement on the Periodic Table.

IPC.7.A

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 ...

atomic-radii-and-effective-nuclear-charge

Atomic Radii and Effective Nuclear Charge

The elements in groups of the periodic table exhibit similar chemical behavior. This similarity occurs because the members of a group have the same number ...

Ionic Radii

Ionic radius is the measure used to describe the size of an ion. A cation always has fewer electrons and the same number of protons as the parent atom; it ...

Ionization Energy

The amount of energy required to remove the most loosely bound electron from a gaseous atom in its ground state is called its first ionization energy ...

Electron Affinity

The electron affinity (EA) is the energy change for adding an electron to a gaseous atom to form an anion (negative ion).



This process can be either ...

Alkali Metals

Group 1 elements are soft and shiny metallic solids. They are malleable, ductile, and good conductors of heat and electricity. The melting points of the ...

Halogens

Group 17 elements, known as halogens, are nonmetals. At room temperature, fluorine and chlorine are gases, bromine is a liquid, and iodine a solid. ...

Noble Gases


The elements in group 18 are noble gases (helium, neon, argon, krypton, xenon, and radon). They earned the name &ldquo;noble&rdquo; because they were ...

Use patterns within the Periodic Table to predict the relative physical and chemical properties of elements.

IPC.7.B

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, ...

Classifying Matter by Composition

Matter: Pure Substances and Mixtures
According to its composition, the matter can be classified into two broad categories &mdash; pure substances and ...

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 ...

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 ...

Explain how physical and chemical properties of substances are related to their usage in everyday life such as in sunscreen, cookware, industrial applications, and fuels.

IPC.7.C

Science concepts. The student knows that relationships exist between the structure and properties of matter. The student is expected to:

Absorbance Spectra and Beer-Lambert Analysis

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