Chromium has an atomic mass of 51.9961 u51.9961 u and consists of four isotopes, cr50,cr50, cr52,cr52, cr53,cr53, and cr54.cr54. the cr52cr52 isotope has a natural abundance of 83.79%83.79% and an atomic mass of 51.9405 u.51.9405 u. the cr54cr54 isotope has a natural abundance of 2.37%2.37% and an atomic mass of 53.9389 u.53.9389 u. the natural abundances of the cr50cr50 and cr53cr53 isotopes exist in a ratio of 0.4579: 1,0.4579: 1, and the cr50cr50 isotope has an atomic mass of 49.9460 u.49.9460 u. determine the atomic mass of the cr53 isotope. cr53 isotope.

The atomic mass of isotope is 52.8367 amu

Explanation:

We know that:

Total percentage abundance of the isotope = 100 %

Percentage abundance of isotopes =

We are given:

Ratio of isotopes = 0.4579 : 1

Percentage abundance of isotope =

Percentage abundance of isotope =

Average atomic mass of an element is defined as the sum of masses of each isotope each multiplied by their natural fractional abundance.

Formula used to calculate average atomic mass follows:

  .....(1)

Let the mass of isotope be 'x'

Mass of isotope = 49.9460 amu

Percentage abundance of = 4.37 %

Fractional abundance of isotope = 0.0437

Mass of isotope = 51.9405 amu

Percentage abundance of isotope = 83.79 %

Fractional abundance of isotope = 0.8379

Mass of isotope = x amu

Percentage abundance of isotope = 9.49 %

Fractional abundance of isotope = 0.0949

Mass of isotope = 53.9389 amu

Percentage abundance of isotope = 2.37 %

Fractional abundance of isotope = 0.0237

Average atomic mass of chromium = 51.9961 amu

Putting values in equation 1, we get:

Hence, the atomic mass of isotope is 52.8367 amu

according to the u.s. department of agriculture, the label of "certified organic" comes with a set of highly regulated standards for environmental stewardship and resource conservation. some of these include maintenance and improvement of soil quality, prevention of ground and surface water contamination, greenhouse gas regulation, encouragement of biodiversity and conservation of water and energy (see references 1). organic practices integrate natural methods such as mulching, plant diversity, native and adapted plants, crop rotation and the introduction of beneficial insects to control pests without synthetic pesticides.

environmental implications of pesticides

synthetic pesticides ensure high crop yields. while effective in achieving this goal, pesticides contaminate soil, air, ground and surface water, as well as the plants and animals that come into contact with these contaminated sources. freshwater and marine organisms are particularly susceptible to pesticides through agricultural runoff. pesticides also reduce soil fertility (necessitating the use of synthetic fertilizers) and can travel far from the original source, contaminating water and air hundreds of miles from the location of application (see references 2).

health implications of organics

although a subject of particular debate, many recent findings show that organic food is healthier than conventionally grown food. according to the usda, an extensive european union-funded study found that organically grown foods contain more beneficial compounds, such as the vitamins and antioxidants needed to combat many diseases (see references 5). organic milk, meat and eggs are regulated to ensure they are free of hormones administered to conventional livestock and poultry.

health implications of pesticides

pesticides affect human health in three ways: through skin contact, inhalation and ingestion. acute and long-term exposure to pesticides can cause serious health problems for farmers who apply them. the majority of other people are affected by drinking contaminated water and eating contaminated marine life (see references 3). pesticides have been linked to neurological disorders, endocrine and reproductive disorders, immune system deficiencies and cancer. according to the world health organization, acute pesticide poisoning (app) is responsible for significant annual mortality, especially in developing nations (see references 4).

other important considerations

not every small farm or business owner can afford the costly certification process required to be considered "certified organic," even if the farm is not using chemicals. "transitional" farms include those that once used chemicals and are now transitioning to organic-only production. in addition, though organic farming methods offer obvious environmental benefit, an organic apple shipped from around the world creates a different set of environmental problems. locally grown food (particularly locally grown, organic food) is key in sustainable food production.