Name: atomic mass and mole calculations
Uploaded: 2023-06-23T15:38:52.000Z
Duration: 1 min 25 s
Channel: JoVE

Bazen atom kütlesi olarak da adlandırılan bir elementin atom ağırlığı, yaklaşık olarak proton ve nötron sayısının toplamına eşittir. Bu, atomik kütle birimleriyle ifade edilir, amu veya Dalton olarak kısaltılır ve periyodik tablodaki kimyasal sembolünün yanında temsil edilir.
Ancak, çoğu elementin nötron sayısı ve dolayısıyla kütleleri bakımından farklılık gösteren birkaç izotopu vardır.
Bu tür elementler için atom ağırlığı, bir elementin tüm izotoplarının ortalama kütlesidir ve nispi bolluklarına veya doğada bulunan her bir izotopun yüzdesine göre ağırlıklandırılır.
Örneğin, klorun doğal olarak oluşan iki izotopu vardır. Klor-35'in kütlesi 34.97 amu ve klor-37'nin kütlesi 36.97 amu'dur.
Klor-35 için %75.77 ve klor-37 için %24.23 olan nispi bollukları ile çarpıldığında ve toplandığında 35.45 amu'luk nihai atom ağırlığı elde edilir.
Klor-35, doğada klor-37'den daha bol miktarda bulunduğundan, klorun atom ağırlığı 35 amu'ya yakındır.

atom ağırlığı

Protonlar ve nötronlar yaklaşık olarak aynı kütleye sahiptir, yaklaşık olarak 1.67 Ã&#151; 10^-24 gram. Bilim insanları bu kütle miktarını bir atomik kütle birimi (amu) veya bir Dalton olarak tanımlarlar. Elektronlar ise protonlardan çok daha küçük bir kütlede bulunur, yalnızca 9.11 Ã&#151; 10^-28 gram veya yaklaşık olarak bir atomik kütle biriminin 1/1800'ü ağırlığındadır. Bu nedenle, elementin genel atomik kütle katkıda bulunmazlar. Bu da, atomik kütle göz önüne alındığında, elektronların kütlesini yok saymak ve atomun kütlesini yalnızca protonların ve nötronların sayısına dayanarak hesaplamak geleneği olduğu anlamına gelir.

Ancak, çoğunlukla doğal olarak bulunan elementler izotoplardan oluştuğu için, böyle elementlerin atomik kütlelerini belirlerken izotopların kütlesini ve doğal bolluğunu dikkate almak önemlidir. Bu durumlarda atomik kütle, her birinin doğal kesirli bolluğuyla çarpılarak elementin tüm izotoplarının kütlesi toplanarak hesaplanır.

Kimyacılar, kimyasal reaksiyona katılan bir bileşiğin atomlarının sayısını belirlemek için genellikle "mol" birimini kullanırlar. Bir elementin moli, gram cinsinden atomik ağırlığıdır, bir bileşiğin moli ise bileşenlerinin atomik ağırlıklarının toplamı olan moleküler ağırlığıdır. Sık kullanılan bir örnek, C_6H_12O_6 kimyasal formülüne sahip glikozun moli hesaplamasıdır. Karbon (C) atomik ağırlığı 12.011 gramdır ve glikozda altı karbon bulunur, bu da toplamda 72.066 gram atomik ağırlığa denk gelir. Hidrojen (H) ve oksijen (O) için aynı hesaplamaları yaparak, glikozun moleküler ağırlığı 180.156 gram olarak bulunur.

Bu metin, <a href="https://openstax.org/books/biology-ap-courses/pages/2-1-atoms-isotopes-ions-and-molecules-the-building-blocks?query=atomic%20mass&target=%7B%22type%22%3A%22search%22%2C%22index%22%3A0%7D#fs-idp140338797859808">Openstax, Biology for AP</a><a href="https://openstax.org/books/biology-ap-courses/pages/2-1-atoms-isotopes-ions-and-molecules-the-building-blocks?query=atomic%20mass&target=%7B%22type%22%3A%22search%22%2C%22index%22%3A0%7D#fs-idp140338797859808">® </a><a href="https://openstax.org/books/biology-ap-courses/pages/2-1-atoms-isotopes-ions-and-molecules-the-building-blocks?query=atomic%20mass&target=%7B%22type%22%3A%22search%22%2C%22index%22%3A0%7D#fs-idp140338797859808">courses. Section 2.1 Atoms, Isotopes, Ions, and Molecules: The Building Blocks</a> and <a href="https://openstax.org/books/anatomy-and-physiology-2e/pages/2-4-inorganic-compounds-essential-to-human-functioning?query=mole&target=%7B%22type%22%3A%22search%22%2C%22index%22%3A0%7D#fs-id1218107">Openstax, Anatomy and Physiology 2e, Section 2.4 Inorganic compounds Essential to Human Functioning</a>

Atom Ağırlığı

Protonlar ve nötronlar yaklaşık olarak aynı kütleye, yaklaşık 1.67 × 10-24 grama sahiptir. Bilim adamları keyfi olarak bu kütle miktarını bir atom kütlesi olarak tanımlarlar ...

Education

JoVE Core

Anatomy and Physiology

Anatomi ve Fizyoloji

Unit 1

Ünite 1

Fundamentals of Chemistry

Kimyanın Temelleri

KEY TERMS AND CONCEPTS

TEMEL TERİMLER VE KAVRAMLAR

Atomic Weight

atomic mass and mole calculations

Atomic mass and mole calculations help explain how much matter is in atoms and compounds. Protons and neutrons have about the same mass, about 1.67 × 10 -24 grams. Scientists define that mass as one atomic mass unit, or amu, also called one Dalton.

Electrons are much lighter than protons. They weigh only 9.11 × 10 -28 grams, or about 1/1800 of an atomic mass unit. Because of that small mass, electrons do not add much to an element’s overall atomic mass. When chemists calculate atomic mass, they usually ignore electrons and use only the protons and neutrons.

Many naturally occurring elements are made of isotopes, which are atoms of the same element with different masses. For these elements, atomic mass must include each isotope’s mass and its natural fractional abundance. Chemists find this by adding the masses of all the isotopes after multiplying each one by how common it is.

Chemists also use the mole to count atoms and compounds in reactions. A mole of an element is its atomic weight in grams. A mole of a compound is the sum of the atomic weights of its parts, and that total is called the molecular weight. Glucose, C6H12O6, is a common example. Carbon has an atomic weight of 12.011 grams, and six carbons in glucose give 72.066 grams. Doing the same for hydrogen and oxygen gives glucose a molecular weight of 180.156 grams.

Atomic Mass and Mole Calculations

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atomic weight

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key terms and concepts

Learn how protons, neutrons, isotopes, and the mole are used to calculate atomic mass and molecular weight with a glucose example for high school chemistry.

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anatomy and physiology

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Atomic Mass and Mole Calculations

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