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MatroZZZ [7]
2 years ago
12

A sample of silicon has an average atomic mass of 28.084amu. In the sample, there are three isotopic forms of silicon. About 92.

22% of silicon atoms are 27.9769amu, which have the mass of 28Si; about 4.68% are 28.9764amu, which have the mass of 29Si, and the isotope 30Si, makes up the remaining 3.10%. Calculate the atomic mass of 30Si. Report your answer with three significant figures
Chemistry
1 answer:
Travka [436]2 years ago
5 0

A sample of silicon has an average atomic mass of 28.084amu. In the sample, there are three isotopic forms of silicon. About 92.22% of silicon atoms are 27.9769amu, which have the mass of 28Si; about 4.68% are 28.9764amu, which have the mass of 29Si, and the isotope 30Si, makes up the remaining 3.10%. Calculate the atomic mass of 30Si. Report your answer with three significant figures <u>The percentage abundance for  </u><u>isotope </u><u>is 3.09 %.</u>

<h3>What is isotopes?</h3>

Isotopes are two or more atom types that share the same atomic number (number of protons in their nuclei), location in the periodic table, and chemical element but have distinct nucleon numbers (mass numbers) as a result of having a different number of neutrons in their nuclei. Although the chemical properties of each isotope of a given element are nearly identical, they differ in their atomic weights and physical characteristics.

The word "isotope" is derived from the Greek words "isos" and "topos," both of which imply "the same location." As a result, the name refers to the fact that various isotopes of a given element occupy the same spot on the periodic table. Scottish physician and author Margaret Todd first used it in a recommendation in 1913.

To learn more about isotopes from the given link:

brainly.com/question/364529

#SPJ4

You might be interested in
what is the percent yield of NaCl if 31.0 g of CuCl reacts with excess NaNo3 to produce 21.2 g of NaCl
olchik [2.2K]
Percentage Yield = (Actual Yield ÷ Theoretical Yield) × 100  

The Actual Yield is given in the question as 21.2 g of NaCl.  However, in order to find the theoretical yield, you have to write a balanced equation and use the mole ratio to calculate the mass of NaCl that would be produced.

Balanced Equation:   CuCl + NaNO₃    →    NaCl + CuNO₃

Moles of CuCl = Mass of CuCl ÷ Molar Mass of CuCl
                         =  31.0 g ÷ (63.5 + 35.5)g/mol
                         = 0.31 mol

the mole ratio of CuCl to NaCl is 1  :  1,
∴ if moles of CuCl = 0.31  mol,

then moles of NaCl = 0.31 mol

Now, Mass of NaCl = Moles of NaCl × Molar Mass of NaCl
                                 =  0.31 mol × (23 + 35.5) g/mol
                                 =  18.32 g

⇒ the THEORETICAL Yield of NaCl, in this case, is 18.32 g.

Now, since Percentage Yield = (Actual Yield ÷ Theoretical Yield) × 100  

⇒ Percentage Yield of NaCl = (21.2g ÷ 18.32g) × 100  
                                                = 115.7 %


NOTE: Typically, the percentage yield of a reaction is less than 100%, however in a case where the mass of the substance is weighed with impurities, then that mass may be in excess of 100% as seen here.
4 0
4 years ago
#1: How are the elements arranged in the modern periodic table?
Alekssandra [29.7K]

1- The correct answer is C :


the elements arranged in the modern periodic table by increasing atomic number.


The explanation:


-The elements in the periodic table are arranged to increase the atomic number. All of these elements display several other trends and we can use the periodic law and table formation to predict their chemical, physical, and atomic properties.


2- The correct answer is C:


strontium, magnesium, calcium, beryllium are the elements which have similar properties.


The explanation:

-strontium, magnesium, calcium, beryllium, these belong to the alkaline earth metal group.

Because the outer electron structure in all of these elements is similar, they all have somewhat similar chemical and physical properties .

3- The correct answer is A :


Potassium


The explanation:


-The elements potassium and sodium have similar chemical properties because they have the same number of valence electrons and form +1 ions.



4- The correct answer is D


The explanation:


Mendeleev didn't include helium, neon, and argon in his periodic table because these elements had not yet been discovered.


5- The correct answer is B:


The periodic law describes trends seen across periods within the periodic table.


The explanation:


When the chemical elements are arranged, there is a pattern called the “periodic law” in their properties, in which elements in the same column (group) have similar properties


4 0
3 years ago
Read 2 more answers
Arrange the three common unit cells in order from least dense to most dense packing. a. face-centered cubic &lt; body-centered c
maks197457 [2]

Answer:

b. primitive cubic < body-centered cubic < face-centered cubic  

Explanation:

The coordination number is defined as <em>the number of atoms (or ions) surrounding an atom (or ion) in a crystal lattice</em>. Its value gives us a measure of how tightly the spheres are packed together. The larger the coordination number, the closer the spheres are to each other.

  • In the <u>primitive cubic</u>, each sphere is in contact with 6 spheres, so its <u>coordination number is 6</u>.
  • In the <u>body-centered cubic</u>, each sphere is in contact with 8 spheres, so its <u>coordination number is 12</u>.
  • In the <u>face-centered cubic</u>, each sphere is in contact with 12 spheres, so its <u>coordination number is 12</u>.

Therefore, the increasing order in density is the primitive cubic first, then the body-centered cubic, and finally the face-centered cubic.

3 0
3 years ago
Which energy profile best shows that the enthalpy of formation of CS2 is 89.4 KJ/mol?
Anna11 [10]

Answer:

Option C. Energy Profile D

Explanation:

Data obtained from the question include:

Enthalpy change ΔH = 89.4 KJ/mol.

Enthalpy change (ΔH) is simply defined as the difference between the heat of product (Hp) and the heat of reactant (Hr). Mathematically, it is expressed as:

Enthalpy change (ΔH) = Heat of product (Hp) – Heat of reactant (Hr)

ΔH = Hp – Hr

Note: If the enthalpy change (ΔH) is positive, it means that the product has a higher heat content than the reactant.

If the enthalpy change (ΔH) is negative, it means that the reactant has a higher heat content than the product.

Now, considering the question given, the enthalpy change (ΔH) is 89.4 KJ/mol and it is a positive number indicating that the heat content of the product is higher than the heat content of the reactant.

Therefore, Energy Profile D satisfy the enthalpy change (ΔH) for the formation of CS2 as it indicates that the heat content of product is higher than the heat content of the reactant.

7 0
3 years ago
Read 2 more answers
What decides if an atom will be a cation or an anion?
JulijaS [17]

The loss or gain of electrons

Explanation:

The loss or gain of electrons determines if an atom will become a cation or anion.

A cation is a positively charge ion

An anion is a negatively charged ion.

In an atom, we have sub-atomic particles:

 Protons are the positively charged particles

 Electrons are negatively charged

  Neutrons carry no charges

Only electrons can be lost or gained in chemical processes that forms cations and anions.

When a neutral atom gains electron, it has more electrons than protons. This makes it negatively charged and we call it an anion.

When a neutral atom loses an electron, the number of protons is more. We call it a cation.

Learn more:

Cations brainly.com/question/4670413

#learnwithBrainly

7 0
4 years ago
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