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Andre45 [30]
2 years ago
7

A typical amount of 99mtc injected for medical imaging is 15.0mci. convert this to decays per second, also called becquerels (bq

, the si unit of activity.\
Chemistry
2 answers:
Maurinko [17]2 years ago
3 0
We are asked in the problem to convert teh unit mci or millicurie to another unit of radioactivity, becquerel. The conversion to be used in this case is <span>1 millicurie [mCi] = 37,000,000 becquerel [Bq] .The problem gives 15 mCi which when multiplied to </span>37,000,000 is equal to 5,550,000,000 bQ
natima [27]2 years ago
3 0

Answer: 0.055\times 10^{10} Bq

Explanation:

Radioactivity is the phenomenon in which a less stable nuclei decomposes to a stable nuclei by releasing some radiations or particles like alpha, beta particles or gamma-radiations.

Radioactivity is measured in units of curie (Ci) or becqerels (bq).

1 millicurie = 10^{-3} Curie

Thus 15 millicurie = \frac{10^{-3}}{1}\times 15=0.015 Curie

1 Curie is equal to 3.7\times 10^{10} Bq

0.015 Curie = \frac{3.7\times 10^{10}}{1}\times 0.015=0.055\times 10^{10} Bq

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1. For which of these elements would the first ionization energy of the atom be higher than that of the diatomic molecule?
Lyrx [107]

Answer: Option (b) is the correct answer.

Explanation:

The energy necessary to remove an electron from a gaseous atom or ion is known as ionization energy.

This means that smaller is the size of an atom more amount of energy has to be supplied to it in order to remove the valence electron. This is because in small atom or element there will be strong force of attraction between the nucleus and electrons.

So, high amount of energy has to be supplied to remove the valence electrons.

As electronic configuration of helium is 1s^{2}. So, due to completely filled valence shell it is more stable in nature.

As a result, we need to provide very high amount of energy to remove an electron from a helium atom.

Thus, we can conclude that out of the given options helium element would the first ionization energy of the atom be higher than that of the diatomic molecule.

7 0
2 years ago
Which of the following represents a propagation step in the monochlorination of methylene chloride (CH2Cl2)?a. CHCl3 + Cl. Right
svetlana [45]

Answer:

B = CHCl2 + Cl2 --> CHCl3 + Cl

Explanation:

Free radical halogenation is a chlorination reaction on Alkane hydrocarbons. This involves the splitting of molecules into radicals/ unstable molecules in the presence of sunlight/ U.V light which ensures bonding of the molecules.

Free radical chlorination is divided into 3 steps which are:

The initiation step

The propagation step

The termination step

So in reference to the question, propagation step involves two steps.

The first step is where the molecule in this case the methylene chloride(CH2Cl2) loses a hydrogen atom and then bond with a chlorine atom radical to give a nethylwnw chloride radical and HCl.

The second step involves the reaction of this methylene chloride got in the first step with chlorine molecule to form trichloride methane and a chlorine radical.

You would find in the attachment the 2 step mechanism.

3 0
2 years ago
How many moles of FeS2 are required to produce 32g of SO2?
nirvana33 [79]

Answer:

<u>So, the right answer is</u>

No. of moles of FeS₂ = 0.25 mole

Explanation:

From the balanced

4 FeS2 + 11 O2 → 2 Fe2O3 + 8 SO2

it is clear that 4 mol  FeS₂ react with O₂ to give Fe₂O₃ and 8 mol of SO₂

First, we have to convert mass of SO₂ into No. of moles as following:

SO₂ has molar mass = 64 g/mol

No. of moles of SO₂ = (mass / molar mass) = (32 g / 64 g/mol) = 0.5 mol

we know that  

4 mol  FeS₂  gives→ 8 mol of SO₂

1 mol  FeS₂  gives→ 2 mol of SO₂

??? mol  FeS₂  gives→ 0.5 mol of SO₂

No. of moles of FeS₂ = (0.5 mol * 1 mol ) / 2 mol = 0.25 mol

<u>So, the right answer is</u>

No. of moles of FeS₂ = 0.25 mol

7 0
2 years ago
Write the balanced Ka and Kb reactions for HSO3- in water. Be sure to include the physical states of each species involved in th
Hunter-Best [27]

Answer:

Ka = [H₃O⁺] [SO₃²⁻] / [HSO₃⁻]

Kb = [OH⁻] [H₂SO₃] / [HSO₃⁻]

Explanation:

An amphoteric substance as HSO₃⁻ is a substance that act as either an acid or a base. When acid:

HSO₃⁻(aq) + H₂O(l) ⇄ H₃O⁺(aq) + SO₃²⁻(aq)

And Ka, the acid dissociation constant is:

<h3>Ka = [H₃O⁺] [SO₃²⁻] / [HSO₃⁻]</h3><h3 />

When base:

HSO₃⁻(aq) + H₂O(l) ⇄ OH⁻(aq) + H₂SO₃(aq)

And kb, base dissociation constant is:

<h3>Kb = [OH⁻] [H₂SO₃] / [HSO₃⁻]</h3>

6 0
1 year ago
A scuba tank contains a mixture of oxygen (O2) and nitrogen (N2) gas. The oxygen has a partial pressure of PO2=5.62MPa. The tota
dmitriy555 [2]

Answer:

21.16 MPa

Explanation:

Partial pressure of oxygen = 5.62 MPa

Total gas pressure = 26.78 MPa

But

Total pressure of the gas= sum of partial pressures of all the constituent gases in the system.

This implies that;

Total pressure of the system = partial pressure of nitrogen + partial pressure of oxygen

Hence partial pressure of nitrogen=

Total pressure of the system - partial pressure of oxygen

Therefore;

Partial pressure of nitrogen= 26.78 - 5.62

Partial pressure of nitrogen = 21.16 MPa

7 0
2 years ago
Read 2 more answers
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