Arsenic Atomic Mass



  1. Arsenic is a naturally occurring allotropic pnictogen and metalloid trace element with atomic symbol As, atomic number 33, and atomic weight 74.92 that is found in water, air, food, and soil, and has a role as a micronutrient.
  2. Arsenic (As) has 33 protons, giving it an atomic number of 33 and, in it's most common isotope, it has 42 neutrons. Atomic mass is equal to (number of protons + number of neutrons).
  3. Arsenic (As) Atomic Data for Arsenic (As) Atomic Number = 33 Atomic Weight = 74.9216 Reference E95: Isotope: Mass: Abundance: Spin: Mag Moment: 75 As: 74.921594: 100%: 3/2 +1.43947: As I Ground State 1s 2 2s 2 2p 6 3s 2 3p 6 3d 1 0 4s 2 4p 3 4 S.
Determines

Molar mass of As = 74.92160 g/mol

Convert grams Arsenic to moles or moles Arsenic to grams


The atomic mass of arsenic = 74.92 g/mol. The mass of 0.0406 mol of arsenic = 0.0406 mol x 74.92 (g/mol) = 3.05 g. The answer is 3.0g. Another way to consider this (same idea - just expressed differently) is what mol% does the As represent in As2S3. Two atoms of arsenic weigh 2 x 74.92 = 149.84 amu (atomic mass units - where 1 amu = molar mass. Physical Properties of Arsenic. Atomic Mass Average: 74.92159; Boiling Point: 876K 603.

Symbol# of AtomsArsenicAs74.921601100.000%



In chemistry, the formula weight is a quantity computed by multiplying the atomic weight (in atomic mass units) of each element in a chemical formula by the number of atoms of that element present in the formula, then adding all of these products together.

Formula weights are especially useful in determining the relative weights of reagents and products in a chemical reaction. These relative weights computed from the chemical equation are sometimes called equation weights.

A common request on this site is to convert grams to moles. To complete this calculation, you have to know what substance you are trying to convert. The reason is that the molar mass of the substance affects the conversion. This site explains how to find molar mass.

Finding molar mass starts with units of grams per mole (g/mol). When calculating molecular weight of a chemical compound, it tells us how many grams are in one mole of that substance. The formula weight is simply the weight in atomic mass units of all the atoms in a given formula.

If the formula used in calculating molar mass is the molecular formula, the formula weight computed is the molecular weight. The percentage by weight of any atom or group of atoms in a compound can be computed by dividing the total weight of the atom (or group of atoms) in the formula by the formula weight and multiplying by 100.

Using the chemical formula of the compound and the periodic table of elements, we can add up the atomic weights and calculate molecular weight of the substance.

The atomic weights used on this site come from NIST, the National Institute of Standards and Technology. We use the most common isotopes. This is how to calculate molar mass (average molecular weight), which is based on isotropically weighted averages. This is not the same as molecular mass, which is the mass of a single molecule of well-defined isotopes. For bulk stoichiometric calculations, we are usually determining molar mass, which may also be called standard atomic weight or average atomic mass.

Chemical properties of arsenic - Health effects of arsenic - Environmental effects of arsenic

33

Atomic mass

74.9216 g.mol -1

Electronegativity according to Pauling

2.0

Density

5.7 g.cm-3 at 14°C

Melting point

814 °C (36 atm)

Boiling point

615 °C (sublimation)

Vanderwaals radius

0.139 nm

Ionic radius

0.222 nm (-2) 0,047 nm (+5) 0,058 (+3)

Isotopes Zebco cardinal 4 replacement spool.

8

Electronic shell

Barley doing any dmg ds3minew. [ Ar ] 3d10 4s2 4p3

Energy of first ionisation

947 kJ.mol -1

Energy of second ionisation

1798 kJ.mol -1

Energy of third ionisation

2736 kJ.mol -1

Standard potential

- 0.3 V (As3+/ As )

Discovered by

The ancients

Arsenic Neutron


Arsenic

Arsenic appears in three allotropic forms: yellow, black and grey; the stable form is a silver-gray, brittle crystalline solid. It tarnishes rapidly in air, and at high temperatures burns forming a white cloud of arsenic trioxide. Arsenic is a member of group Va of the periodic table, which combines readily with many elements.
The metallic form is brittle, tharnishes and when heated it rapidly oxidizes to arsenic trioxide, which has a garlic odor. The non metallic form is less reactive but will dissolve when heated with strong oxidizing acids and alkalis.

Applications

Arsenic compounds are used in making special types of glass, as a wood preservative and, lately, in the semiconductor gallium arsenade, which has the ability to convert electric current to laser light. Arsine gas AsH3, has become an important dopant gas in the microchip industry, although it requires strict guidelines regarding its use because it is extremely toxic.
During the 18th, 19th, and 20th centuries, a number of arsenic compounds have been used as medicines; copper acetoarsenite was used as a green pigment known under many different names.

Arsenic in the environment

Arsenic can be found naturally on earth in small concentrations. It occurs in soil and minerals and it may enter air, water and land through wind-blown dust and water run-off. Arsenic in the atmosphere comes from various sources: vulcanoes release about 3000 tonnes per year and microorganisms release volatile methylarsines to the extent of 20.000 tonnes per year, but human activity is responsible for much more: 80.000 tonnes of arsenic per year are released by the burning of fossil fuels.

Despite its notoriety as a deadly poison, arsenic is an essential trace element for some animals, and maybe even for humans, although the necessary intake may be as low as 0.01 mg/day.
Arsenic is a component that is extremely hard to convert to water-soluble or volatile products. The fact that arsenic is naturally a fairly a mobile component, basically means that large concentrations are not likely to appear on one specific site. This is a good thing, but the negative site to it is that arsenic pollution becomes a wider issue because it easily spreads. Arsenic cannot be mobilized easily when it is immobile. Due to human activities, mainly through mining and melting, naturally immobile arsenics have also mobilized and can now be found on many more places than where they existed naturally.

A little uncombined arsenic occurs naturally as microcrystalline masses, found in Siberia, Germany, France, Italy, Romania and in the USA. Most arsenic is found in conjuction with sulfur in minerals such as arsenopyrite (AsFeS), realgar, orpiment and enargite. Non is mined as such because it is produced as a by-product of refining the ores of other metals, such as copper and lead. World production of arsenic, in the form of its oxide, is around 50.000 tonnes per year, far in excess of that required by industry. China is the chief exporting country, followed by Chile and Mexico. World resources of arsenic in copper and lead ores exceed 10 million tonnes.

Health effects of arsenic

Arsenic is one of the most toxic elements that can be found. Despite their toxic effect, inorganic arsenic bonds occur on earth naturally in small amounts. Humans may be exposed to arsenic through food, water and air. Exposure may also occur through skin contact with soil or water that contains arsenic.
Levels of arsenic in food are fairly low, as it is not added due to its toxicity. But levels of arsenic in fish and seafood may be high, because fish absorb arsenic from the water they live in. Luckily this is mainly the fairly harmless organic form of arsenic, but fish that contain significant amounts of inorganic arsenic may be a danger to human health.
Arsenic exposure may be higher for people that work with arsenic, for people that live in houses that contain conserved wood of any kind and for those who live on farmlands where arsenic-containing pesticides have been applied in the past.
Exposure to inorganic arsenic can cause various health effects, such as irritation of the stomach and intestines, decreased production of red and white blood cells, skin changes and lung irritation. It is suggested that the uptake of significant amounts of inorganic arsenic can intensify the chances of cancer development, especially the chances of development of skin cancer, lung cancer, liver cancer and lymphatic cancer.
A very high exposure to inorganic arsenic can cause infertility and miscarriages with women, and it can cause skin disturbances, declined resistance to infections, heart disruptions and brain damage with both men and women.
Finally, inorganic arsenic can damage DNA.

A lethal dose of arsenic oxide is generally regarded as 100 mg.
Organic arsenic can cause neither cancer, nor DNA damage. But exposure to high doses may cause certain effects to human health, such as nerve injury and stomachaches.

Environmental effects of arsenic

The arsenic cycle has broadened as a consequence of human interference and due to this, large amounts of arsenic end up in the environment and in living organisms. Arsenic is mainly emitted by the copper producing industries, but also during lead and zinc production and in agriculture. It cannot be destroyed once it has entered the environment, so that the amounts that we add can spread and cause health effects to humans and animals on many locations on earth.

Plants absorb arsenic fairly easily, so that high-ranking concentrations may be present in food. The concentrations of the dangerous inorganic arsenics that are currently present in surface waters enhance the chances of alteration of genetic materials of fish. This is mainly caused by accumulation of arsenic in the bodies of plant-eating freshwater organisms. Birds eat the fish that already contain eminent amounts of arsenic and will die as a result of arsenic poisoning as the fish is decomposed in their bodies.

More information on properties of arsenic

Read more on arsenic in water

Information on arsenicosis


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