please help me ;-; I need help grades are in tomorrow

Answer:

New energy level is n = 2

Explanation:

ΔE = energy released by e⁻ transition n = 7 to n(final) = - h·c/λ

h = Planck's Constant = 6.63 x 10⁻³⁴ j·s

c = speed of light in vacuum = 3 x 10⁸ m/s

λ = wavelength = 397 nm = 3.97 x 10⁻⁷ m

ΔE = - (6.63 x 10⁻³⁴j·s )(3 x 10⁸ m/s)/(3.97 x 10⁻⁷ m) = - 5.01 x 10⁻¹⁹ joule

Note: this is the transitional energy 'released' by the electron moving from n = 7 energy level to n(final) energy level. As released energy, the system should be represented by an exothermic process hence, the negative value for ΔE = - h·c/λ. The equivalent amount of energy is an absorption of electromagnetic energy (EMR) to promote the electron from n(final) to n = 7 and this would be endothermic as noted with a +h·c/λ .

The Bohr Model of the electron behavior postulates electron transitions by the release of a 'discrete' amount of EMR as emission spectra defined by the expression ...

ΔE = E(final) - E(initial) => E(final) = ΔE + E(initial)

E(n) = positional (potential) energy content of electron while in energy level n and is defined by the expression E(n) = -R(H)/n²

R(H) = Rydberg Constant = 2.18 x 10⁻¹⁸ joules

n = positional energy level (in this case) = 7

E₇ = -2.18 x 10⁻¹⁸ j / (7)² = -4.45 x 10⁻²⁰ j (potential energy of n = 7 electron)

E(final) = ΔE + E₇ = (-5.01 x 10⁻¹⁹ j)  + (-4.45 x 10⁻²⁰ j) = -4.455 x 10⁻¹⁹ j

E(final) = -R(H)/n²

=> n = SqrRt[R(H)/E(final)] = SqrRt[(-2.18 x 10⁻¹⁸ j)/(-4.455 x 10⁻¹⁹)] ≅ 2

New energy level is n = 2

Answer:

The initial volume in mL is 5959.2 mL

Explanation:

As the number of moles of a gas increases, the volume also increases.  Hence, number of moles and volumes are directly proportional i.e

n ∝ V

Where n is the number of moles and V is the volume

Then, n = cV

c is the proportionality constant

∴n/V = c

Hence n₁/V₁ = n₂/V₂

Where n₁ is the initial number of moles

V₁ is the initial volume

n₂ is the final number of moles

and V₂ is the final volume.

From the question,

n₁ = 0.693 moles

V₁ = ?

n₂ = 0.928 moles

V₂ = 7.98 L

Putting the values into the equation

n₁/V₁ = n₂/V₂

0.693 / V₁ = 0.928 / 7.98

Cross multiply

∴ 0.928V₁ = 0.693 × 7.98  

0.928V₁ = 5.53014

V₁ = 5.53014/0.928

V₁ = 5.9592 L

To convert to mL, multiply by 1000

∴ V₁ = 5.9592 × 1000 mL

V₁ = 5959.2 mL

Hence, the initial volume in mL is 5959.2 mL

Based on the information given, the image represents a negatively charged fluoride atom (Option B)

An atom is composed of a centrally placed nucleus (containing protons and neutrons) and a cloud of electrons revolving round it.

From the question given above, the following data were obtained:

Charge = Proton – Electron

Charge = 9 – 10

Charge = –1

Note

Element with proton number of 9 is fluorine

Thus, we can conclude that the image represents a negatively charged fluoride ion (Option B)

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Answer:

B

Explanation:

Answer: The answer is either A or C. I'm leaning more towards A.

Answer:

I think its C :)

Answer:

CO + 3H2 -> H20 + CH4 :)) !!

Answer:

220.9g of water are required

Explanation:

The molar enthalpy of vaporization is defined as the heat released when 1 mole of water changes from liquid to gas.

For water, 1 mole releases 40.79kJ. To release 500kJ are necessaries:

500kJ * (1mol / 40.79kJ) = 12.26 moles are necessaries

To convert moles to grams we must use the molar mass (H2O = 18.02g/mol):

12.26 moles * (18.02g / 1 mol) =

Answer: The volume of hydrogen produced is 0.122 L

Explanation:

To calculate the moles :

[tex]\text{Moles of solute}=\frac{\text{given mass}}{\text{Molar Mass}}[/tex]

[tex]\text{Moles of solute}={\text{Molarity}}\times {\text{Volume in L}}[/tex]  

[tex]\text{Moles of} Mg=\frac{5.00g}{24g/mol}=0.208moles[/tex]

[tex]\text{Moles of} HCl=[/tex][tex]0.100moldm^{-3}\times 0.1dm^3=0.01mol[/tex]

The balanced chemical equation is:

[tex]Mg+2HCl\rightarrow MgCl_2+H_2[/tex]  

According to stoichiometry :

2 moles of require = 1 mole of

Thus 0.01 moles of [tex]HCl[/tex] will require=[tex]\frac{1}{2}\times 0.01=0.005moles[/tex]  of [tex]Mg[/tex]

Thus is the limiting reagent as it limits the formation of product and is the excess reagent.

As 2 moles of give = 1 mole of

Thus 0.01 moles of [tex]HCl[/tex] give =[tex]\frac{1}{2}\times 0.01=0.005moles[/tex]  of [tex]H_2[/tex]

According to ideal gas equation:

[tex]PV=nRT[/tex]

P = pressure of gas = 1.0 atm  (SATP)

V = Volume of gas = ?  

n = number of moles = 0.005

R = gas constant =[tex]0.0821Latm/Kmol[/tex]

T =temperature =[tex]25^0C=(25+273)K=298K[/tex] (SATP)

[tex]V=\frac{nRT}{P}[/tex]

[tex]V=\frac{0.005mol\times 0.0820 L atm/K mol\times 298K}{1.0atm}=0.122L[/tex]

Thus volume of hydrogen produced is 0.122 L

Answer:12

Explanation:

Answer:

C. pressure and temperature

Explanation:

For each substance, the conditions defining the critical point are the critical temperature, the critical pressure, and the critical density.

Hope this helped!!!

Pressure and temperature are the properties defining the critical point of matter in a phase diagram. The correct option is C.

A phase diagram is a visualization of a material's physical states under various situations of pressure and temperature.

Pressure is on the y-axis of a typical phase diagram, and temperature is on the x-axis. A phase transition when we cross the lines or curves on the phase diagram.

The pressure and temperature point on a phase diagram where a material's liquid and gaseous phases merge into a single phase.

The merged single phase is known as a supercritical fluid above the critical point temperature.

Phase diagrams are graphical representations of the connections between the various phases that appear in a system under equilibrium conditions.

Thus, the correct option is C.

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Answer:

Title.

Abstract.

Introduction.

Method.

Results and analysis.

Discussion.

Conclusion.

References.

Option D I got it right

ANSWER: C (ENERGY WAS RELEASED WHEN THE MOLECULE WAS FORMED FROM ITS ELEMENTS.)

HOPE THE OTHER PERSON IS WRONG!

Answer:

Actinides

Explanation:

The actinides are valuable primarily because they are radioactive.

Answer:

it is analog signal, your welcome

Analog Signal is the correct answer

Hope it helps you

Explanation:

Answer:

3

Explanation:

from the KLMN shell

K has the maximum of 2 electrons

M has the maximum of 8

M has the maximum of 18

so 12 electrons fell on M shell which is the third one

that's all....have fun

Answer:

the reaction is: Na2CO3 + 2HCl ===》 2NaCl + H2O + CO2(g)

Answer:

1 respuesta. fórmula empírica = CH2

Explanation:

Translatation: 1 Answer. empirical formula = CH2

The solute wether electrolyte or a nonelectrolyte, has the greater effect on the boiling point when a given amount of each solute is dissolved in the same mass of water The nonelectrolyte does because it dissociates into ions.

Solute refers to substances or liquid which can readily dissolve in a solvent. It's concentration is lower to that of solvent.

Therefore, The solute wether electrolyte or a nonelectrolyte, has the greater effect on the boiling point when a given amount of each solute is dissolved in the same mass of water The nonelectrolyte does because it dissociates into ions

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Answer:

D: The electrolyte does because it dissociates into ions.

Explanation:

Answer:

I think it's thermochemical reaction and sorry if it's wrong

Answer:

The angle of incoming sunlight varies at different places

Answer: This answer is multiple choices.

1. Land and water have different heat capacities.

And

3. The angle of incoming sunlight varies at different places.

Explanation: I kept seeing other people only putting in one answer, so I used this answer from someone else. Credit to them!

Answer:

Explanation:  CH3COOH(aq) + H2O(l) ↔ CH3COO-(aq) + H3O+(aq) acid base ... sulfuric acid can react with either OH- or. H.

Answer:

it is b

Explanation: As the carbon dioxide is released, calcite is precipitated or redeposited on cave walls, ceilings and floors. As the redeposited minerals build up after countless water drops, a stalactite is formed.

Nitrogen transmutes to form an isotope of oxygen. The superscript for oxygen is 17

The subscript for hydrogen is 1

Cobalt-59 accepts a neutron to form a new isotope. The subscript for cobalt is 27

Answer:

Oxygen = 17

Hydrogen = 1

Cobalt = 27

Explanation:

Answer:

K = 0.5

Explanation:

Based on the reaction:

PCl₃ + Cl₂ ⇄ PCl₅

The equilibrium constant, K, is defined as:

K = P PCl₅ / P PCl₃ * P Cl₂

Where P represent the pressure at the equilibrium for each one of the gases involved in the equilibrium.

As:

P PCl₅ = 1.0atm

P PCl₃ = 1.0atm

P Cl₂ = 2.0atm

K = 1.0atm / 1.0atm * 2.0atm

Answer:

All of our energy comes from the sun.

Explanation:

The sun sends out huge amounts of energy through its rays every day. Without the sun, life on earth would not exist, since our planet would be totally frozen.

The term for the heaviness on something's surface that exerts a force over an area is pressure. The correct option is b. pressure

From the question, we are to determine the term for the heaviness on something's surface that exerts a force over an area.

Here, we are talking about pressure.

Pressure is defined as the physical force exerted on an object. Mathematically, it is defined as the perpendicular force per unit area.

That is,

[tex]P = \frac{Force}{Area}[/tex]

Where P is the pressure

The units of pressure are Newtons per square meter (N/m²), Pascals etc.

Hence, the term for the heaviness on something's surface that exerts a force over an area is pressure. The correct option is b. pressure

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