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SVETLANKA909090 [29]
3 years ago
15

Can anyone help me with this asap?

Chemistry
1 answer:
tresset_1 [31]3 years ago
3 0

Answer:

Explanation:

1) During the diagnosis of thyroid disease a 10 g sample of I-131 is used. After a period of 32 days, how much sample is still radio active.?

Answer:

0.625 g

Explanation:

HL = Elapsed time/half life

32 days/8 days = 4

At time zero = 10 g

At 1st half life = 10/2 = 5 g

At 2nd half life = 5/2 = 2.5 g

At 3rd half life = 2.5 /2 = 1.25 g

At 4th half life = 1.25 / 2 = 0.625 g

After 32 days still 0.625 g of I-131 remain radioactive.

2) what was the original mass of sample Tc-99 that was used to locate the brain tumor If 0.10 g of a sample remains after 30 days? (half life 6 days)

Answer:

0.32 g.

Explanation:

Half life = time elapsed / HL

Half life = 30 days / 6 days = 5

At 5th half life = 0.10 g

At 4th half life = 0.2 g

At 3rd half life =  0.4 g

At 2nd  half life = 0.8 g

At 1st half life = 0.16 g

At time zero = 0.32 g

The original amount was 0.32 g.

3) write the beta decay equation of I-131?

Equation:

¹³¹I₅₃  →  ¹³¹Xe₅₄ + ⁰₋₁e

Beta radiations are result from the beta decay in which electron is ejected. The neutron inside of the nucleus converted into the proton an thus emit the electron which is called β particle.

The mass of beta particle is smaller than the alpha particles.

They can travel in air in few meter distance.

These radiations can penetrate into the human skin.

The sheet of aluminium is used to block the beta radiation

¹³¹I₅₃  →  ¹³¹Xe₅₄ + ⁰₋₁e

The beta radiations are emitted in this reaction. The one electron is ejected and neutron is converted into proton.

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I need the answers to these quick!!
Dmitrij [34]

I haven't taken biology in a few years, so I may be wrong, but to me it looks like mitosis, since it only divides once, and if I can see the picture correctly it looks like each cell contains the same amount of chromosomes, but I can't see the picture very well. If it helps here are some differences between meiosis and mitosis:

1. Cell Division

Mitosis: A somatic cell divides once. Cytokinesis (the division of the cytoplasm) occurs at the end of telophase.

Meiosis: A reproductive cell divides twice. Cytokinesis happens at the end of telophase I and telophase II.

2. Daughter Cell Number

Mitosis: Two daughter cells are produced. Each cell is diploid containing the same number of chromosomes.

Meiosis: Four daughter cells are produced. Each cell is haploid containing one-half the number of chromosomes as the original cell.

3. Genetic Composition

Mitosis: The resulting daughter cells in mitosis are genetic clones (they are genetically identical). No recombination or crossing over occur.

Meiosis: The resulting daughter cells contain different combinations of genes. Genetic recombination occurs as a result of the random segregation of homologous chromosomes into different cells and by the process of crossing over (transfer of genes between homologous chromosomes).

4. Length of Prophase

Mitosis: During the first mitotic stage, known as prophase, chromatin condenses into discrete chromosomes, the nuclear envelope breaks down, and spindle fibers form at opposite poles of the cell. A cell spends less time in prophase of mitosis than a cell in prophase I of meiosis.

Meiosis: Prophase I consists of five stages and lasts longer than prophase of mitosis. The five stages of meiotic prophase I are leptotene, zygotene, pachytene, diplotene, and diakinesis. These five stages do not occur in mitosis. Genetic recombination and crossing over take place during prophase I.

5. Tetrad Formation

Mitosis: Tetrad formation does not occur.

Meiosis: In prophase I, pairs of homologous chromosomes line up closely together forming what is called a tetrad. A tetrad consists of four chromatids (two sets of sister chromatids).

6. Chromosome Alignment in Metaphase

Mitosis: Sister chromatids (duplicated chromosome comprised of two identical chromosomes connected at the centromere region) align at the metaphase plate (a plane that is equally distant from the two cell poles).

Meiosis: Tetrads (homologous chromosome pairs) align at the metaphase plate in metaphase I.

7. Chromosome Separation

Mitosis: During anaphase, sister chromatids separate and begin migrating centromere first toward opposite poles of the cell. A separated sister chromatid becomes known as daughter chromosome and is considered a full chromosome.

Meiosis: Homologous chromosomes migrate toward opposite poles of the cell during anaphase I. Sister chromatids do not separate in anaphase I.

I can add the similarities between them if you need. This work is not mine, I got it from thoughtCo.

Good luck :)

3 0
3 years ago
Determine the molarity for the fixer Sodium carbonate decahydrate (I dissolved 127.62 grams of sodium carbonate for every 4 lite
grin007 [14]

Answer:

0.112 M.

Explanation:

  • Molarity is the no. of moles of solute in a 1.0 L of the solution.

M = n/V.

<em>M = (mass/molar mass)solute x (1000/V of the solution).</em>

mass = 127.62 g.

molar mass = 286.138 g/mol.

V of the solution = 4.0 L = 4000.0 mL.

<em>∴ M = (mass/molar mass)solute x (1000/V of the solution)</em> = (127.62 g / 286.138 g/mol) x (1000 / 4000.0 mL) = <em>0.1115 M ≅ 0.112 M.</em>

4 0
4 years ago
1. Which of the following statements about separation techniques is correct?
vagabundo [1.1K]

Answer: A

Explanation:

4 0
4 years ago
Please help!!! (im really bad at chemistry)
Lubov Fominskaja [6]

Answer:

1000ml/1L

Explanation:

8 0
3 years ago
Ozone, O3(g), is a form of elemental oxygen produced during electrical discharge. Is ΔH∘f for O3(g) necessarily zero? Yes or no
Ivan
The answer for your question is <span>No. This is because in given conditions, it is not the most stable form of oxygen's element. It will not equate into zero because there will be charge remained after balancing the equation. 
</span>
6 0
4 years ago
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