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kondaur [170]
2 years ago
13

Enter the atomic symbol for an atom with a mass number of 72 and an atomic number of 33.

Chemistry
1 answer:
GarryVolchara [31]2 years ago
7 0

Answer:

Hafnium i think it would be

Explanation:

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A chemist wishing to do an experiment requiring 47-Ca2+ (half-life = 4.5 days) needs 5.0 μg of the nuclide. What mass of 47-CaCO
NARA [144]

Answer:

5.8μg

Explanation:

According to the rate or decay law:

N/N₀ = exp(-λt)------------------------------- (1)

Where N = Current quantity,  μg

            N₀ = Original quantity, μg

             λ= Decay constant day⁻¹

              t =  time in days

Since the half life is 4.5 days, we can calculate the  λ from (1) by  substituting N/N₀ = 0.5

0.5 = exp (-4.5λ)

ln 0.5  = -4.5λ

-0.6931 = -4.5λ

λ =   -0.6931 /-4.5

  =0.1540 day⁻¹

Substituting into (1)  we have :

N/N₀ = exp(-0.154t)----------------------------- (2)

To receive 5.0 μg of the nuclide with a delivery time of 24 hours or 1 day:

N = 5.0 μg

N₀ = Unknown

t = 1 day

Substituting into (2) we have

[5/N₀]   = exp (-0.154 x 1)

    5/N₀        = 0.8572

N₀  =  5/0.8572

     =    5.8329μg

    ≈     5.8μg

The Chemist must order 5.8μg  of 47-CaCO3

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2 years ago
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Describe why large size and attraction to others
uranmaximum [27]
The largest in size usually attracks a population of what it is and whether the people think it is popular
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How is the oxidation state of a transition metal determined from the chemical formula ?
Vera_Pavlovna [14]

Answer:

Explanation:

In a chemical formula, the oxidation state of transition metals can be determined by establishing the relationships between the electrons gained and that which is lost by an atom.

We know that for compounds to be formed, atoms would either lose, gain or share electrons between one another.

The oxidation state is usually expressed using the oxidation number and it is a formal charge assigned to an atom which is present in a molecule or ion.

To ascertain the oxidation state, we have to comply with some rules:

  • The algebraic sum of all oxidation numbers of an atom in a neutral compound is zero.
  • The algebraic sum of all the oxidation numbers of all atoms in an ion containing more than one kind of atom is equal to  the charge on the ion.

For example, let us find the oxidation state of Cr in Cr₂O₇²⁻

This would be:  2x + 7(-2) = -2

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We see that the oxidation number of Cr, a transition metal in the given ion is +6.

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3 years ago
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How do water particles move in a wave? A. They move forward with the wave. B. They move in a circular motion. C. They move up an
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