Someone please help will mark as brainliest

Answer:

Explanation:

To find the number of moles in a substance given it's number of entities we use the formula

[tex]n = \frac{N}{L} \\[/tex]

where n is the number of moles

N is the number of entities

L is the Avogadro's constant which is

6.02 × 10²³ entities

From the question we have

[tex]n = \frac{1.81 \times {10}^{24} }{6.02 \times {10}^{23} } \\ = 3.006644...[/tex]

We have the final answer as

Hope this helps you

Answer:

Strontium [tex]94_{38}[/tex]Sr

Explanation:

By the law of mass conversion the nuclear mass remains constant in a reaction which means initial mass and atoic number will be equal to final atomic number and atomic mass respectively.

²³⁵₉₂U + ¹₀n → ? + ¹³⁹₅₄Xe + 3 ¹₀n

Here atomic mass =

235 + 1 = A + 139+3 ( A -= atomic mass of ?)

A = 236 - 142

A = 94

And, atomic number would be =

92 = B + 54

B = 92 - 54

B = 38

So, the atomic number of ? will be 38 and atomic mass will be = 94

The element with 38 atomic number is = Strontium [tex]94_{38}[/tex]Sr

The missing species in the equation is ⁹⁴₃₈Sr

Let the missing species be ᵇₐY

We can write the equation as:

²³⁵₉₂U + ¹₀n → ᵇₐY + ¹³⁹₅₄Xe + 3¹₀n

235 + 1 = b + 139 + 3(1)

236 = b + 139 + 3

236 = b + 142

Collect like terms

236 – 142 = b

92 + 0 = a + 54 + 0

92 = a + 54

Collect like terms

92 – 54 = a

b = 94

a = 38

ᵇₐY => ⁹⁴₃₈Y => ⁹⁴₃₈Sr

The balanced equation is:

²³⁵₉₂U + ¹₀n → ⁹⁴₃₈Sr + ¹³⁹₅₄Xe + 3¹₀n

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Answer:

curdling.

Explanation:

Answer:

walk to work, carpool to work, drive alone to work

Explanation:

Answer:

It is Na2O because it doesn't show any acidic properties.

Answer:

2NaCl + 1CaF²--------》2NaF + 1CaCl²

Answer:

2NaCl + CaF2 >>> 2NaF + CaCl2

Answer:

1. B

2. C

3. C

4. B

Explanation:

1. An atom of sulfur has an atomic number of 16. It has three electron shells and six valence electrons, therefore, it belongs to period 3, group VIA of the periodic table

2. Bromine has an atomic number of 35. It belongs to period 4 group VIIA of the periodic table. Therefore, it has four electron shells and seven valence electrons.

3. Argon has an atomic number of 18. It belongs to period 3, group IVA of the periodic table. Therefore, it has three electron shells and eight valence electrons.

4. The Lewis dot model use structures that represent the valence electrons of atoms within a molecule existing as lone pairs or when involved in bonding. They can be used to draw electrons that are involved in a collision during a chemical reaction.

Answer:

Some cells, such as the frog egg cells shown here, divide every 30 minutes, and others take as long as a year! The table below compares the length of different cell cycles. 2. With each cell cycle, two cells form from one cell.

After 3 hours, the number of cells formed from one frog egg cell has been 64.

The division of the frog cell occurs every 30 minutes. Thus in 3 hours, the number of divisions occurs:

30 minutes = 1 division

3 [tex]\times[/tex] 60 minutes = [tex]\rm \dfrac{1}{30}\;\times\;180[/tex]

= 6 divisions.

The number of cells formed after n divisions can be given by = [tex]\rm 2^n[/tex]

where n is the number of division cycles.

The number of cells after 6 division cycles = [tex]\rm 2^6[/tex]

The number of cells = 64.

After 3 hours, the number of cells formed from one frog egg cell has been 64.

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Answer:

with 20 protons (p=20) and 22 neutrons (n=22)? 47 ... Listed below are the charges and masses of four ... a) +2,2 amu c ) +1, 1 amu least b) ... pudding” Model.

Explanation:

Answer:

7amu

Explanation:

Atoms are composed of three particles.  The proton, neutron, and electron.  

The mass of the atom in amu is just the number of protons and neutrons in the nucleolus since they both have a mass of about 1 amu.  Electrons are not counted since they have an incredibly small mass that ultimately does not matter.  

This atom has 3 protons (positively charged particle) and 4 neutrons (particle with no charge) which together gives a mass of 7 amu.

the group : 2

periode : 6

block = 2

atomic number = 56

We can divide the periodic system into several parts:

1. Block s: groups 1 and 2 (having a configuration of 1s-7s) consist of active metals except for H (non-metals) and He (noble gases)

2. Block p: group 13-18 (has a 2p-6p configuration), also called a representative element because it includes metals, non-metals and metalloids

3. Block d: group 3-12 (having the 3d-6d configuration), are transition metal elements

4. Block f: Lanthanides and Actinides (having a 4f-5f configuration), are inner transition elements that are also metal

The element with the electron configuration :  [Xe]6s²

The outer shell 6s² :

Electron configuration :

1s², 2s², 2p⁶, 3s², 3p⁶, 4s², 3d¹⁰, 4p⁶, 5s², 4d¹⁰, 5p⁶, 6s² : electron =56

group⇒valence electron ⇒2

period⇒the greatest value of the quantum number n⇒6

The element that is in period 6, and belongs to group 2 and has the atomic number 56 and in the block s

Answer:

26.981539

Explanation:

The density of the sample : 0.827 g/L

In general, the gas equation can be written  

[tex]\large {\boxed {\bold {PV = nRT}}}[/tex]

where  

P = pressure, atm , N/m²

V = volume, liter  

n = number of moles  

R = gas constant = 0.082 l.atm / mol K (P= atm, v= liter),or 8,314 J/mol K (P=Pa or N/m2, v= m³)

T = temperature, Kelvin  

n= 1 mol

MW Neon = 20,1797 g/mol

mass of Neon :

[tex]\tt mass=mol\times MW\\\\mass=1\times 20,1797 =20.1797~g[/tex]

The density of the sample :

[tex]\tt \rho=\dfrac{m}{V}\\\\\rho=\dfrac{20,1797}{24.4}=0.827~g/L[/tex]

or We can use the ideal gas formula ta find density :

[tex]\tt \rho=\dfrac{P\times MW}{RT}\\\\\rho=\dfrac{1\times 20.1797}{0.082\times 298}\\\\\rho=0.826~g/L[/tex]

Answer:

Chemists keep track of how electrons are transferred between atoms in a reaction using an oxidation number. If the oxidation number of an element in the reaction increases or becomes less negative, the element has been oxidized, while a decreased or more negative oxidation number means the element has been reduced.

Answer:

It has more electrons in the product than in the reactant

Explanation:

A p e x

Answer:

Fluorine has 9 protons and 9 electrons

Iodine has 53 protons and 53 electrons

Explanation:

Fluorine has 9 protons and 9 electrons and Iodine has 53 protons and 53 electrons.

An electron is defined as a subatomic particle which is charged negatively either bound to an atom or not it means they are freely found. The nucleus of an atom is made up of electron, proton and neutron. The electron is a basic particle and electron is not made of anything.

The nature of electron is free it means they are present freely in nature and an atom consist of electron.The main function of electron is that function of negatively- charged component of an atom.

The electrons are primary function of current conducting and electrons number as well as atomic number of an element is always same or equal. There is no size of electron but the mass of electron is 9×10^-31.

Therefore, Fluorine has 9 protons and 9 electrons and Iodine has 53 protons and 53 electrons.

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Answer:

Neutron pull together Neutron

Answer:

i think.its D ddddddddddddd

Answer:

c

Explanation:

Answer:

(1) conversion of mass to energy

Explanation:

Nuclear fission: In nuclear fission, an unstable atom splits into two or more smaller pieces that are more stable, and releases energy in the process. The fission process also releases extra neutrons, which can then split additional atoms, resulting in a chain reaction that releases a lot of energy.

The primary result of a nuclear fission reaction is the conversion of energy to mass.

Hence, option 2 is the answer.

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Answer:

c

Good luck on your assessment!

Answer:

true

Explanation:

i hope this is right your welcome

Answer:

The definition of Condensation is the conversion of a vapour or gas to a liquid, so therefore, this can be proven as a true statement.

Answer:

30 moles of water will produced.

Explanation:

Given data:

Number of moles of O₂ react = 15 mol

Number of moles of water formed = ?

Solution:

Chemical equation:

2H₂ + O₂      →     2H₂O

Now we will compare the moles of water with oxygen.

                  O₂           :          H₂O

                   1             :            2

                   15           :           2×15 = 30 mol

30 moles of water will produced.

Answer:

D

Explanation:

I took a study island on this

Answer:

A mass and distance

Explanation:

Answer:

Explanation:

The volume of a substance when given the density and mass can be found by using the formula

[tex]volume = \frac{mass}{density} \\[/tex]

From the question we have

[tex]volume = \frac{50}{1.59} \\ = 31.446540...[/tex]

We have the final answer as

Hope this helps you

Answer:

A

Explanation:

Considering the definition of chemical formula, the correct answer is option A): number of valence electrons in each atom.

A chemical formula is the representation of the elements that make up a compound and the proportion in which they are found, or the number of atoms that make up a molecule.

In other words, a chemical formula is an alphanumeric expression that is used to indicate the composition of a chemical substance and that is constructed from the symbols of its constituent elements, affected by numerical subscripts that report the number of atoms of each element that it is part of the substance.

In summary, the correct answer is option A): number of valence electrons in each atom.

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Answer: The most recent three layers are the Paleozoic, Mesozoic, and Cenozoic. These layers represent the last 500 million years of life on earth. In the Paleozoic, you find fish, amphibian, and reptile fossils (in that order), but never dinosaurs, birds, modern mammals, or even flowering plants.

Explanation:

Most recent fossils are found in Paleozoic, Mesozoic, and Cenozoic. The type of rock is sedimentary rock.

Fossils are defined as the well-preserved remnants of plants and animals whose carcasses were buried beneath ancient seas, lakes, and rivers in sediments like sand and muck. There are several ways that fossils are created, but the majority occur when an animal or plant dies in a wet environment and is buried in mud and silt.

A new fossil species has been found in a fossil deposit close to Llandrindod Wells in central Wales, according to an international team of experts. Numerous characteristics of Cambrian fossil Mierridduryn bonniae are shared by both.  Rock and sediment layers build up on top of one another over time. The oldest and youngest rock layers are always found in reverse order.

Thus, most recent fossils are found in Paleozoic, Mesozoic, and Cenozoic. The type of rock is sedimentary rock.

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The average atomic mass of Rubidium : 85.226 u

Isotopes are atoms whose no-atom has the same number of protons while still having a different number of neutrons.  

So Isotopes are elements that have the same Atomic Number (Proton)  

Atomic mass is the average atomic mass of all its isotopes  

In determining the mass of an atom, as a standard is the mass of 1 carbon-12 atom whose mass is 12 amu  

Mass atom X = mass isotope 1 . % + mass isotope 2.%  

The abundance of 85Rb is 80% and the abundance of 87Rb is 19.8%, so the average atomic mass of Rubidium :

[tex]\tt the~average~atomic~mass=0.8\times 85+0.198\times 87\\\\the~average~atomic~mass=\boxed{\bold{85.226~u}}[/tex]