What is a volcano that is erupting or has erupted in the last 100 years called?

antimony has two naturally occuring isotopes, sb121sb121 and sb123sb123 . sb121sb121 has an atomic mass of 120.9038 u120.9038 u

Luda [366]

Considering the definition of atomic mass, isotopes and atomic mass of an element, sb121 has a percent natural abundance of 0.5726 or 57.26% and sb123 has a percent natural abundance of 0.4284 or 42.84%.

<h3>Definition of atomic mass</h3>

The atomic mass is obtained by adding the number of protons and neutrons in a given nucleus of a chemical element.

<h3>Definition of isotope</h3>

Isotopes are the chemical elements in which atomic numbers are the same, but the number of neutrons is different.

<h3>Definition of atomic mass</h3>

The atomic mass of an element is the weighted average mass of its natural isotopes.

This is, the atomic masses of elements are usually calculated as the weighted average of the masses of the different isotopes of each element, considering the relative abundance of each of them.

<h3>Percent natural abundance of each isotope</h3>

In this case, antimony has two naturally occuring isotopes, sb121 and sb123. You know:

sb121 has an atomic mass of 120.9038 u.
sb121 has a percent natural abundance of x.
sb123 has an atomic mass of 122.9042 u.
sb123 has a percent natural abundance of 1 -x (or, what is the same, the abundance is 100% - x%, since both isotopes form 100% of the element.)
Antimony has an average atomic mass of 121.7601 u

The average mass of antimony is expressed as:

121.7601 u= 120.9038 u x + 122.9042 u× (1 -x)

Solving:

121.7601 u= 120.9038 u x + 122.9042 u - 122.9042 u x

121.7601 u - 122.9042 u= 120.9038 u x - 122.9042 u x

(-1.1441 u)= (-2.0014) x

(-1.1441 u)÷ (-2.0014)= x

So, 1 -x= 1- 0.5716 → <u><em>1-x= 0.4284 or 42.84%</em></u>

Finally, sb121 has a percent natural abundance of 0.5726 or 57.26% and sb123 has a percent natural abundance of 0.4284 or 42.84%.

Learn more about average atomic mass:

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5 0

2 years ago

For each balanced reaction, indicate the total number of atoms in the table below.

Afina-wow [57]

(i) Make ammonia number of atoms on reactant side is 8 and on product side is 8. (ii) Separate water number of atoms on reactant side is 6 and on product side is 6. (iii) Combust methane number of atoms on reactant side is 9 and number of atoms on product side is 9.

<h3>What is Balanced Chemical Equation ?</h3>

The balanced chemical equation is the equation in which the number of atoms on the reactant side is equal to the number of atoms on the product side in an equation.

(i) Make Ammonia

First we have to write the balanced chemical equation

N₂ + 3H₂ → 2NH₃

Reactant side Product side

N = 2 N = 2

H = 6 H = 6

So total number of atoms on product and reactant side is 8.

(ii) Separate Water

First we have to write the balanced chemical equation

2H₂O → 2H₂ + O₂

Reactant side Product side

H = 4 H = 4

O = 2 O = 2

So total number of atoms on product and reactant side is 6.

(iii) Combust methane

First we have to write the balanced chemical equation

CH₄ + 2O₂ → 2H₂O + CO₂

Reactant side Product side

C = 1 C = 1

H = 4 H = 4

O = 4 O = 4

So total number of atoms on product and reactant side is 9.

Thus from the above conclusion we can say that For each balanced reaction, the total number of atoms are

Reaction Total number of atoms

Reactant side Product side

Make Ammonia 8 8

Separate Water 6 6

Combust Methane 9 9

Learn more about the Balanced Chemical Equation here: brainly.com/question/26694427

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Disclaimer: The question was given incomplete on the portal. Here is the complete question.

Question: For each balanced reaction, indicate the total number of atoms in the table below.

Reaction Total number of atoms

Reactant side Product side

Make Ammonia _________ __________

Separate Water _________ __________

Combust Methane _________ __________

3 0

2 years ago

What's the empirical and molecular weight of C14H22N4O8? What's the molecular formula of C14H22N4O8?

Inessa05 [86]

374u

187u

C₁₄H₂₂N₄O₈

Explanation:

To find the molecular weight of the compound C₁₄H₂₂N₄O₈ we simply sum that atomic masses of the given elements in the compound.

The empirical weight is determined by using the simplest ratio of the elements involved in the compound;

Molecular weight of C₁₄H₂₂N₄O₈;

atomic mass of C = 12g/mol

H = 1g/mol

N = 14g/mol

O = 16g/mol

Molecular weight = 14(12) + 22(1) + 4(14) + 8(16)

= 168 + 22 + 56 + 128

= 374u

Empirical weight:

Empirical formula:

C₁₄ H₂₂ N₄ O₈

14 : 22 : 4 : 8

divide by 2:

7 : 11 : 2 : 4

empirical formula C₇H₁₁N₂O₄

empirical weight = $\frac{molecular weight}{2}$ = $\frac{374}{2}$ = 187u

The molecular formula is the actual combination of atoms in a compound. so the molecular formula of the compound is C₁₄H₂₂N₄O₈

learn more:

Molecular mass brainly.com/question/5546238

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8 0

3 years ago

How many atoms are in 5.70 x 10^32 mol of Rn?

Alex73 [517]

To find amount of atoms from mol, multiply the mole amount by Avogadro’s number

5.70x10^32 x 6.02x10^23

= 3.43x10^56 atoms

5 0

3 years ago

How does ionization energy change from left to right on a period?

Olenka [21]

As the atomic radius decreases, it becomes harder to remove an electron that is closer to a more positively charged nucleus. They experience a weaker attraction to the positive charge of the nucleus. Ionization energy increases from left to right in a period and decreases from top to bottom in a group.

5 0

4 years ago