An atom of an element has two electrons in the first energy level and five electrons in the second energy level. Write the electron configuration and name the element. How many unpaired electrons does an atom of this element have?

Answer:

75603.86473 K

Explanation:

Given that:

The 1st excited electronic energy level of He atom = 3.13 × 10⁻¹⁸  J

The objective of this question is to estimate the temperature at which the ratio of the population will be 5.0 between the first excited state to the ground state.

The formula for estimating the ratio of population in 1st excited state to the ground state can be computed as:

[tex]\dfrac{N_2}{N_1} = e ^{^{-\dfrac{(E_2-E_1)}{KT}}} = e ^{^{-\dfrac{(\Delta E)}{KT}}}[/tex]

From the above equation:

Δ E = energy difference =  3.13 × 10⁻¹⁸  J

k = Boltzmann constant = 1.38 × 10⁻²³  J/K

[tex]\dfrac{N_2}{N_1} = 0.5[/tex]

Thus:

[tex]0.05 =e^{^{ -\dfrac{3.13 \times 10^{-18} \ J}{1.38\times 10^{-23 \ J/K}\times T}}}[/tex]

[tex]In (0.05) = { -\dfrac{3.13 \times 10^{-18} \ J}{1.38\times 10^{-23 \ J/K}\times T}}}[/tex]

[tex]-3.00 = { -\dfrac{3.13 \times 10^{-18} \ J}{1.38\times 10^{-23 \ J/K}\times T}}}[/tex]

[tex]-3.00 = -226811.5942 \times \dfrac{1}{T}[/tex]

[tex]T = \dfrac{-226811.5942}{-3.00 }[/tex]

T = 75603.86473 K

Answer:

Explain some of the uses of metals based on their properties.

Explanation:

Metals have a shiny or metallic luster and are good conductors of heat and electricity, they can be bent and pounded in various shapes, so they can be used on cars, coins, some pipes, keys, and and a flag.

Answer:

adding a catalyst will increase the reaction rate.

Explanation:

im like 95% sure thats right.

Answer:

A. C. D

Explanation:

ap ex

Answer:

Pentyl Ethanoate, CH3COOC5H11, which smells like bananas, is produced from the esterification reaction: CH3COOH(aq) +C5H11OH(aq) → CH3COOC5H11(aq) + H … 2O(l) A reaction uses 3.58g of CH3COOH and 4.75g of C5H11OH and has a yield of 45.00%. Determine the mass of ester that foorms

Answer:

Cultivated rice paddies

Drilling of natural deposits

Fossil fuel use

Burning of biomass

Landfills

Explanation:

The bulk of the methane released into the atmosphere are as a result of various human activities.

Answer:

B

Explanation:

Newton's third law. states that:

Action and reaction are equal and opposite.

Answer:

A heating curve graphically represents the phase transitions that a substance undergoes as heat is added to it. The plateaus on the curve mark the phase changes. The temperature remains constant during these phase transitions.

Answer:

[tex]23.093\ \text{torr}[/tex]

Explanation:

[tex]M_g[/tex] = Molar mass of glucose = 180.2 g/mol

[tex]M_w[/tex] = Molar mass of water = 18 g/mol

[tex]m_g[/tex] = Mass of glucose = 76.6 g

[tex]m_w[/tex] = Mass of water = [tex]250\times 1\ \text{g/mL}=250\text{g}[/tex]

[tex]P_0[/tex] = Vapor pressure of pure water at 25°C = 23.8 torr

The mole fraction of glucose is

[tex]x_g=\dfrac{\dfrac{m_g}{M_g}}{\dfrac{m_g}{M_g}+\dfrac{m_w}{M_w}}=\dfrac{\dfrac{76.6}{180.2}}{\dfrac{76.6}{180.2}+\dfrac{250}{18}}\\\Rightarrow x_g=0.0297[/tex]

Mole fraction of the solute would be

[tex]\dfrac{P_0-P}{P_0}=x_g\\\Rightarrow 0.0297=\dfrac{23.8-P}{23.8}\\\Rightarrow P=23.8-0.0297\times23.8\\\Rightarrow P=23.093\ \text{torr}[/tex]

The vapor pressure of the solution is [tex]23.093\ \text{torr}[/tex].

Answer:

This means that a solution must be cooled to a lower temperature than the pure solvent in order for freezing to occur.

Explanation:

Answer:

Freezing Point Depression. The freezing point of a solution is less than the freezing point of the pure solvent. This means that a solution must be cooled to a lower temperature than the pure solvent in order for freezing to occur

The enthalpy : 320.3 kJ/mol

The change in enthalpy in the formation of 1 mole of the elements is called enthalpy of formation  

The enthalpy of formation measured in standard conditions (25 ° C, 1 atm) is called the standard enthalpy of formation (ΔHf °)  

Based on the principle of Hess's Law,

the change in enthalpy of a reaction will be the same even though it is through several stages or ways  

Reaction

2Fe (s) + 3Cl₂ (g) → 2FeCl₃ (s) ∆H° = -800.0 kJ/mol  x 2

4Fe (s) + 6Cl₂ (g) → 4FeCl₃ (s) ∆H° = -1600.0 kJ/mol

Si(s) + 2 Cl₂ (g) → SiCl₄ (s) ∆H° = -640.1 kJ/mol

Reverse

SiCl₄ (s) → Si(s) + 2 Cl₂ (g) ∆H° = 640.1 kJ/mol x 3

3SiCl₄ (s) → 3Si(s) + 6Cl₂ (g) ∆H° = 1920.3 kJ/mol

------------------------------------------------------------------------ +

3 SiCl₄ (s) + 4 Fe (s) → 4 FeCl₃ (s) + 3 Si (s) ∆H° = 320.3 kJ/mol

The enthalpy for the formation of 4 moles of [tex]\rm FeCl_3[/tex] has been 320.3 kJ/mol.

The enthalpy of formation of 1 mole at standard temperature and pressure has been termed the standard enthalpy of formation.

The reaction enthalpy to be calculated has reactants of 3 moles of [tex]\rm SiCl_4[/tex], and 4 moles of Fe.

The enthalpy for the formation of [tex]\rm SiCl_4[/tex] has been -640.1 kJ/mol.

The enthalpy for the dissociation of [tex]\rm SiCl_4[/tex] has been the reverse of the formation reaction = +640.1 kJ/mol.

The enthalpy for the dissociation of 3 moles of [tex]\rm SiCl_4[/tex] has been = 3 [tex]\times[/tex] 640.1 kJ/mol.

The enthalpy for the dissociation of 3 moles of [tex]\rm SiCl_4[/tex] has been = 1920.3 kJ/mol.

The enthalpy for the formation of 2 moles of [tex]\rm FeCl_3[/tex] = -800 kJ/mol

The enthalpy for the formation of 4 moles of [tex]\rm FeCl_3[/tex] = -1600 kJ/mol.

The final reaction has 3 moles of  [tex]\rm SiCl_4[/tex], and 4 moles of [tex]\rm FeCl_3[/tex].

Thus, the final enthalpy of reaction will be: 1920 kJ/mol + (-1600 kJ/mol)

The final enthalpy of reaction will be = 320.3 kJ/mol.

For more information about the enthalpy of reaction, refer to the link:

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Answer:

I believe its 1,2, and 5

Explanation:

C D E

temperature of medium

type of wave

type of medium

Answer:

residue is whatever remains after something else has been removed while filtrate is the liquid or solution that has passed through a filter, and which has been separated from the filtride.

filtration id done by placing a filter paper on the beaker or container then pour the filtride then let it settle and it will pass through and you will have the fitrate and residue

Explanation:

Complete Question

Calculate the pH during the titration of 20.00 mL of 0.1000 M trimethylamine, (CH3)3N(aq), with 0.2000 M HClO4(aq) after 9.48 mL of the acid have been added.Kb of trimethylamine = 6.5 x 10-5.

Answer:

The pH is  [tex]pH = 9.84[/tex]  

Explanation:

From  the question we are told that

   The  volume of trimethylamine, (CH3)3N(aq) is [tex]V_{t} = 20.00mL[/tex]

    The concentration of trimethylamine is [tex]C_t = 0.1000 \ M[/tex]  

    The  volume of HClO4(aq) is [tex]V_{h} = 9.48 mL[/tex]

    The  concentration of  HClO4(aq) is  [tex]C_h = 0.200 M[/tex]

      The Kb  value is  [tex]K_b = 6.5 * 10^{-5}[/tex]

Generally the the pOH of this reaction is mathematically represented as

       [tex]pOH = pK_b + log [\frac{N_h}{N_b} ][/tex]

Here [tex]N_h[/tex] is the number of moles of acid which is evaluated as

      [tex]N_h = C_h * V_h[/tex]

=>    [tex]N_h = 0.200 * 9.48[/tex]

=>    [tex]N_h = 1.896[/tex]

Here [tex]N_t[/tex] is the number of moles of acid which is evaluated as

      [tex]N_t = C_t * V_t[/tex]

=>    [tex]N_t = 0.100 * 20[/tex]

=>    [tex]N_t = 2[/tex]

So

     [tex]pOH = -log(K_b) + log [\frac{N_h}{N_b} ][/tex]

     [tex]pOH = -log(6.5*10^{-5}) + log [\frac{1.896}{2} ][/tex]

=>   [tex]pOH = 4.1639[/tex]

Generally the pH is mathematically represented as

       [tex]pH = 14 - pOH[/tex]

=>    [tex]pH = 14 - 4.1639[/tex]  

=>    [tex]pH = 9.84[/tex]  

Answer:

[tex]0.192\ \text{M}[/tex]

Explanation:

A = Absorbance of solution

E = Molar absorptivity

l = Length of cuvette = 1 cm

c = Concentration of solution

Beer's law is given by

[tex]A=Elc[/tex]

The equation of a straight line is given by

[tex]y=mx+c[/tex]

Comparing the above equations we get

Value on [tex]y[/tex] axis = A = Absorbance of solution = 0.23

[tex]m[/tex] = Slope of line = El = Molar absorptivity multiplied with length = [tex]1.2\times 1\ \text{M}^{-1}[/tex]

[tex]x[/tex] = Value of x axis = c = Concentration of solution

So we get

[tex]c=\dfrac{A}{El}\\\Rightarrow c=\dfrac{0.23}{1.2\times 1}\\\Rightarrow c=0.192\ \text{M}[/tex]

The molar concentration of the sample is [tex]0.192\ \text{M}[/tex]

Answer:

14.57g

Explanation:

Given parameters:

Mass of dish + ball  = 15.6g

Initial volume of water in the cylinder  = 26.7mL  

Final volume of water in the cylinder  = 38.9mL

Mass of dish = ?

Unknown

Mass of the ball = ?

Solution;

 Since the mass of ball and dish is 15.6g,

 Mass of the ball  =Mass of ball + dish  - mass of the dish

 Insert the parameters and solve;

 Mass of the ball  = 15.6g  - 1.03g  = 14.57g

Answer:

I am sure that the C one is correct

Answer:

how is this college level..im doing this in middle school..

Explanation:

Answer:

Its B

Explanation:

Answer:

Chloroplasts absorb sunlight and use it in conjunction with water and carbon dioxide gas to produce food for the plant. Chloroplasts capture light energy from the sun to produce the free energy stored in ATP and NADPH through a process called photosynthesis.

Explanation:

Answer:

ion is missing

Explanation:

Answer:

0.16 L

Explanation:

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

Mole = 0.0806 mole

Molarity = 0.490 M

Volume =?

Molarity is simply defined as the mole of solute per unit litre of the solution. Mathematically, it is expressed as:

Molarity = mole /Volume

With the above formula, we can obtain the volume of the solution as illustrated below:

Mole = 0.0806 mole

Molarity = 0.490 M

Volume =?

Molarity = mole /Volume

0.490 = 0.0806/volume

Cross multiply

0.490 × volume = 0.0806

Divide both side by 0.490

Volume = 0.0806 / 0.490

Volume of solution = 0.16 L

Thus, the volume of the solution is 0.16 L.

A solution is a mixture of solute in the solvent. The volume of the solution is 0.16 L.

A solution is a mixture of solute in the solvent.

An example of a solution is a mixture of salt in water.

Given,

Moles = 0.0806 mol [tex]\rm CaCl_2[/tex]

Molarity = 0.490 M

To find: the volume of the solution

[tex]Molarity = \dfrac{n}{V}[/tex]

Putting the values

[tex]0.490 M = \dfrac{ 0.0806}{V}\\\\0.490 M \times V = 0.0806\\\\Divide\; both\;side\; with\; 0.490\\\\V= \dfrac{ 0.0806}{0.490}=0.16 L[/tex]

Thus, the volume so the solution is 0.16 l.

Learn more about the solution, here:

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Answer:

3 blue beads

1 red beads

4 green beads

Explanation:

The compound given:

               Ca₃PO₄

Elements in the compound are:

Ca

P

O

  Number of atoms are :

Ca - 3

P - 1

O  - 4

blue beads to model Calcium

red beads to model Phosphorus

green beads to model Oxygen

    3 blue beads

    1 red beads

   4 green beads

Answer:

i can only help with 2 :( atimic mass is: 35.453  and number of electrons is:17

Explanation:

Answer:

c. Potential decreases and kinetic increases.

Explanation:

As the boulder is rolling down the hill, potential energy decreases as kinetic energy increases.

Please Brainliest me

Answer: sulfur

Explanation:

Answer:

its sulfur babes

Explanation:

Answer:

The temperature of the Nitrogen after throttling is  [tex]T_2 = 300 \ K[/tex]

Explanation:

From the question we are told that

   The  temperature is  [tex]T_1 = 300 \ K[/tex]

    The pressure is  [tex]P = 200 \ kPa = 200 * 10^{3} \ Pa[/tex]

    The pressure after being  [tex]P_1 = 100 \ kPa = 100 * 10^{3} \ Pa[/tex]

Generally from the first law of thermodynamics we have that

      [tex]Q - W = \Delta U + \Delta K[/tex]

Here [tex]\Delta U[/tex]  is the change internal  energy which is mathematically represented as

            [tex]\Delta U = C_p (T_2 - T_1)[/tex]

Here      [tex]C_p[/tex] is the specific heat of the gas at constant pressure

        [tex]\Delta K[/tex]  is the change kinetic energy which is negligible

         Q  is the thermal  energy  which is Zero for an adiabatic process

         W  is the work done and the value is zero given that the gas was throttled adiabatically

So

      [tex]0= \Delta U +0[/tex]

=>   [tex]\Delta U = 0[/tex]

=>  [tex](T_2 - 300) = 0[/tex]

=>   [tex]T_2 = 300 \ K[/tex]

Answer:

Sphere

Explanation:

The shape of the s-sublevel is spherical in shape.

This sublevel has an azimuthal quantum number of 0 and it is spherical in shape;

Answer:

The amount of groundwater is decreasing.

Explanation:

In an ecosystem like the state of Georgia where the water table has become lower it means that the amount of groundwater in the ecosystem is decreasing.

Ecosystem is defined as a system which consists of all living organisms and the physical components with which the living beings interact. The abiotic and biotic components are linked to each other through nutrient cycles and flow of energy.

Energy enters the system through the process of photosynthesis .Animals play an important role in transfer of energy as they feed on each other.As a result of this transfer of matter and energy takes place through the system .Living organisms also influence the quantity of biomass present.By decomposition of dead plants and animals by microbes nutrients are released back in to the soil.

Learn more about ecosystem,here:

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#SPJ5

Answer:

In this section, please include the if/then statements you developed during your lab activity for each location on the map. These statements reflect your predicted outcomes for the experiment.

Location One: Select two events that you predict will be observed. If I explore two continental plates at a convergent boundary, then I will observe:

earthquakes

faults

ocean formation

mountains

volcanoes

island chains

seafloor spreading

Location Two: Select three events that you predict will be observed. If I explore two continental plates at a divergent boundary, then I will observe:

earthquakes

faults

ocean formation

mountains

volcanoes

island chains

seafloor spreading

Location Three: Select three events that you predict will be observed. If I explore two continental plates at a transform boundary, then I will observe:

earthquakes

faults

ocean formation

mountains

volcanoes

island chains

seafloor spreading

This is all I have for now! Hope this can help! :)