(HELP FAST )What occurs when a pure liquid substance is cooled?

Answer:

Explanation:

The atom X has 1 1 protons (atomic number) and thus would have 11 electrons. This means the atom X would have 1 valence electron in it's outermost shell. While the atom Y has 17 protons (atomic number) and thus would have 17 electrons. This means the atom Y would have 7 electrons in it's outermost shell.

The type of bond this atoms (X and Y) would form is an Ionic (or electrovalent) bond. This bond/combination involves the transfer of electron(s) and a molecule is not formed as seen in the image below.

The molar mass of the gas : 18 x 10⁻³ kg/mol

Given

An unknown gas has one third the root mean square speed of H2 at 300 K

Required

the molar mass of the gas

Solution

Average velocities of gases can be expressed as root-mean-square (V rms)  

[tex]\large {\boxed {\bold {v_ {rms} = \sqrt {\dfrac {3RT} {Mm}}}}[/tex]

T = temperature, Mm = molar mass of the gas particles  , kg/mol

R = gas constant 8,314 J / mol K  

v rms An unknown gas = 1/3 v rms H₂

v rms H₂ :

[tex]\tt v_{rms}=\sqrt{\dfrac{3\times 8.314\times 300}{2.10^{-3}} }\\\\v_{rms}=1934.22[/tex]

V rms of unknown gas =

[tex]\tt \dfrac{1}{3}\times 1934.22=644.74[/tex]

[tex]\tt 644.74^2=\dfrac{3\times 8.314\times 300}{M_{gas}}\\\\M_{gas}=18\times 10^{-3}~kg/mol[/tex]

Answer:

C. It does not participate in a decay series.

Explanation:

From this statement, we can deduce that a radioisotope that forms a stable isotope after it undergoes radioactive decay suggests that it does not participate in a decay series.

Answer:

C

Explanation:

because that's just the answer:)

Answer:

b it is easy its b

Explanation:

Answer:

B

Explanation:

Answer:

1.Creates environmental hazards

2.Can contribute to global warming processe

3.Can pollute harmful and toxic things in the air

4.has harmful gases that can hurt the environment including the water and soil

5.A waste of space that is taking up the earth

6.full of rubbish and toxins that can effect the environment

7.can hurt humans and animals because of the toxic chemicals produced in the air

8.Make the land soil weaker because of the bad toxins and chemicals

Answer:

12.5mg of technetium-99 remain

Explanation:

When a radioactive isotope decays in the time, its concentration follows the equation:

ln[A] = -kt + ln[A]₀

Where [A] could be taken as the mass of radioactive isotope after time t (18h),

k is rate constant = ln 2 / Half-Life = ln 2 / 6hours = 0.1155hours⁻¹

[A]₀ is initial amount of the isotope = 100.0mg

Replacing:

ln[A] = -0.1155hours⁻¹ *18hours+ ln[100.0mg]

ln[A] = 2.5257

[A] =

Answer:Read explanation

Explanation:

A polar molecule has a net dipole as a result of the opposing charges (i.e. having partial positive and partial negative charges) from polar bonds arranged asymmetrically. Water (H2O) is an example of a polar molecule since it has a slight positive charge on one side and a slight negative charge on the other. A non polar substance we be the opposite of what I said

Answer:

Molecule

Explanation:

Its simple definition

Answer:

Magnesium has an outer energy level of n=3 with two electrons in in its energy level. Therefor Magnesium has 2 valance electrons.

Explanation:

Answer:

10 electrons

Explanation:

The d sublevel has 5 orbitals, so can contain 10 electrons max. And the 4 sublevel has 7 orbitals, so can contain 14 electrons max. In the picture below, the orbitals are represented by the boxes. You can put two electrons in each box.

Answer:

10

Explanation:

you're welcome

Answer:

I believe the answer is A, sorry if i'm wrong

Explanation:

Answer:

zany

Explanation:

Answer:

a fresh start

Explanation:

Answer:

MgF2 magnesium fluoride

Answer: Sea Level

Explanation: facts

BeSO₄ + 2NH₄OH → Be( OH)₂ + (NH₄)₂SO₄

Given

Reaction

BeSO₄ + 2NH₄OH → Be( ...)₂ + (NH₄)₂SO₄

Required

The products

Solution

There are two possible displacement reactions

Single replacement if one element replaces or reduces another element in the compound and forms a new compound

A + BC ⇒ AC + B

Double replacement if both the cations and anions of the two compounds in the reactant swap positions to form 2 new compounds in the product

AB + CD ⇒ AD + CB

Thus, the product is Be(OH)₂

Answer:

OH

Explanation:

The enthalpy for the reaction : ΔH = -132

Given

Reaction and the enthalpy

Required

the enthalpy

Solution

Hess Law

Reaction 1 reverse :

A + B = G + C  ΔH = -277

Reactions 2 and 3 remain the same (unchanged)

C + F = A         ΔH = 303

D = B + H         ΔH = -158

Add up all the reactions and remove the same compound from two different sides

D + F = G + H  ΔH = -132

Answer:

4

The molecule here is LiSO4, because the definition of a molecule is 2 or more molecules chemically bound together. A coefficient of 4 is another way of saying "4 molecules of LiSO4"

Answer:

Ionic bonding is the complete transfer of valence electron(s) between atoms. It is a type of chemical bond that generates two oppositely charged ions. In ionic bonds, the metal loses electrons to become a positively charged cation, whereas the nonmetal accepts those electrons to become a negatively charged anion.

Explanation:

Answer:

Ionic bonding is the complete transfer of valence electron(s) between atoms. It is a type of chemical bond that generates two oppositely charged ions. In ionic bonds, the metal loses electrons to become a positively charged cation, whereas the nonmetal accepts those electrons to become a negatively charged anion.

Explanation:

Answer:

75 g

Explanation:

Mass=Density x Volume so therefore you do the density which is 1.5 g/mL times the volume which is 50.0 mL so you get 75 g because the mL cancel out in the label!

Answer:

The volume of water to be added is 0.175 liters of water

Explanation:

The given concentration of the nitric acid = 55% (M/M)

The mass of the nitric acid solution = 100 gm

The concentration solution is to diluted to = 20% (M/M)

The 100 g 55%(M/M) nitric acid solution gives 55g nitric acid in 100 g of solution

Therefore, to have 20% (M/M) nitric acid solution with the 55 g nitric acid, we get

Let "x" represent the volume of the resulting solution, we have;

20% of x = 55 g of nitric acid

∴ 20/100 × x = 55 g

x = 55 g × 100/20 =  275 g

The mass of extra water to be added = The mass of the 20%(M/M) solution solution of nitric acid - The current mass of the 55%(M/M) solution of nitric acid

The mass of extra water to be added = 275 g - 100 g = 175 g

Volume = Mass/Density

The density of water ≈ 1 g/ml

∴ The volume of water to be added that gives 175 g of water =  175 g/(1 g/ml) = 175 ml. = 0.175 l

The volume of water to be added = 0.175 liters of water.

Answer:

The kinetic energy of the boy is 20 times that of the kinetic energy of the girl.

Explanation:

It is given that,

The mass of the boy is 20 times that of girl.

Let [tex]m_b[/tex] and [tex]m_g[/tex] are the mases of boy and the girls.

A boy and girl are running with the same speed.

The formula for the kinetic energy is given by :

[tex]E=\dfrac{1}{2}mv^2[/tex]

Where m is mass and v is speed

As speed is same for both boy and girl.

Kinetic energy of a girl,

[tex]K_g=\dfrac{1}{2}m_gv^2[/tex] ...(1)

As [tex]m_b=20m_g[/tex]

Kinetic energy of a boy,

[tex]K_b=\dfrac{1}{2}m_bv^2\\\\=\dfrac{1}{2}\times 20m_g\times v^2\ ....(2)[/tex]

From equation (1) and (2) :

[tex]\dfrac{K_g}{K_b}=\dfrac{\dfrac{1}{2}m_gv^2}{\dfrac{1}{2}m_bv^2}\\\\=\dfrac{\dfrac{1}{2}m_gv^2}{\dfrac{1}{2}\times 20 m_gv^2}\\\\\dfrac{K_g}{K_b}=\dfrac{1}{20}\\\\K_b=20K_g[/tex]

So, the kinetic energy of the boy is 20 times that of the kinetic energy of the girl. Hence, this is the required solution.

Answer:

temperature increases energy

Answer:parrallel

Explanation:

Answer:

0.06739 mol Cu(SO₄)₂

General Formulas and Concepts:

Chemistry - Atomic Structure

Explanation:

Step 1: Define

17.23 g Cu(SO₄)₂

Step 2: Identify Conversions

Molar Mass of Cu - 63.55 g/mol

Molar Mass of S - 32.07 g/mol

Molar Mass of O - 16.00 g/mol

Molar Mass of Cu(SO₄)₂ - 63.55 + 2(32.07) + 8(16.00) = 255.69 g/mol

Step 3: Convert

[tex]17.23 \ g \ Cu(SO_4)_2(\frac{1 \ mol \ Cu(SO_4)_2}{255.69 \ g \ Cu(SO_4)_2} )[/tex] = 0.067386 mol Cu(SO₄)₂

Step 4: Check

We are given 4 sig figs. Follow sig fig rules and round.

0.067386 mol Cu(SO₄)₂ ≈ 0.06739 mol Cu(SO₄)₂

Answer:

Absorbs energy

Explanation:

As an electron in an atom moves from the ground state to the excited state, the electron absorbs energy.

Electrons moves around in permissible orbits around the nucleus of an atom.

The transition of electrons from one level to another involves loss or gain of energy.

Answer:

The answer to this question is given below in the explanation section.

Explanation:

The Bohr model depicts an atom as a small, positively charged nucleus surrounded by electrons.These electrons travel in circular orbit around the nucleus similar in structure to the solar system,except electrostatic forces rather than gravity provide attraction.Electron orbit around the nucleus resembles that of planets around the sun in the solar system.

        The Bohr model was an improvement  on the earlier cubic model(1902),the plum pudding model(1904) the saturnine model (1904) the rutherford model (1911) since the Bohr model is a quantum physics based modification of the Rutherford may source combine the two:the Rutherford-Bohr model

Although revolutionary at the time,the Bohr model is a relatively primitive model of the hydrogen atom compared to the  valence shell atom.As an initial hypothesis it was derived as a first order approximation to describe the hydrogen atom.Due to its simplicity and correct results for selected systems.

In 913 Bohr suggested that electrons could only have certain classical motions: