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Answer:

n = 5 to n = 6 absorption

n = 9 to n = 6 emission

n = 6 to n = 4 emission

n = 6 to n = 7 absorption

Explanation:

According to the Bohr's model of the atom. An electron in an atom may absorb energy and move from a lower energy level to a higher energy level. This requires absorption of energy that is equal to the energy difference between the two levels.

Similarly, an electron may move from a higher to a lower energy level, releasing energy that is equal to the energy difference between the higher and the lower level. This is known as emission.

Hence, if the electron is moving from a lower energy level to a higher energy level, an absorption has taken place, e.g n = 5 to n = 6

When an electron moves from a higher energy level to a lower energy level, an emission has taken place e.g n = 9 to n = 6

Answer: The number of molecules of gas the flask contains is [tex]0.674\times 10^{23}[/tex]

Explanation:

According to ideal gas equation:

[tex]PV=nRT[/tex]

P = pressure of gas = 1 atm   (STP)

V = Volume of gas = 2.50 L

n = number of moles  = ?

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

T =temperature = 273K (STP)

[tex]n=\frac{PV}{RT}[/tex]

[tex]n=\frac{1atm\times 2.50L}{0.0821 L atm/K mol\times 273K}=0.112moles[/tex]

According to Avogadro's law:

1 mole of gas at STP contains =[tex]6.023\times 10^{23}[/tex] molecules

Thus 0.112moles of gas at STP contains = [tex]\frac{6.023\times 10^{23}}{1}\times 0.112=0.674\times 10^{23}[/tex] molecules

The number of molecules of gas the flask contains is [tex]0.674\times 10^{23}[/tex]

Answer:

1.70 L

Explanation:

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

Pressure (P) = constant = 1.2 atm

Initial volume (V1) = 1.25 L

Initial temperature (T1) = 293 K

Final temperature (T2) = 398 K

Final volume (V2) =?

Since the pressure is constant, the gas is obeying Charles' law. Thus, we can obtain the new volume (V2) of the gas by applying the Charles' equation as shown below:

V1/T1 = V2/T2

1.25 / 293 = V2 /398

Cross multiply

293 × V2 = 1.25 × 398

293 × V2 = 497.5

Divide both side by 293

V2 = 497.5 / 293

V2 = 1.70 L

Therefore, the new volume of the gas is 1.70 L.

Answer:

C. Only 2s and 2p may hybridize; these orbitals contain valence electrons used in bonding.

Explanation:

Carbon has four valence electrons (2s² 2p²), in several organic compounds it forms four bonds and as this element has two types of orbitals to join, 2s and 2p, it is expected that a compound like methane has two types of C-H bonds, but this is not the case, as all its orbital atoms are the same.

In a process called hybridization, s orbitals and p orbitals are combined in an atom. Depending on the amount of p orbitals that are combined, the hybrid orbitals can be sp (one orbital 2s and one 2p are combined), sp² (the 2s orbital combines with two 2p orbitals) and sp³(the orbital 2s combines with three 2p orbitals).

The carbon atom has the presence of 6 electrons. The valence bond theory hybridized the 2s and 2p orbital for the bonding, as they have valence bonds.

The valence bond theory has been the atomic hybridization of the atoms that results in the formation of the bonds.

The carbon atom has 4 valence electrons present in the bonding valence orbitals. The orbitals combine as sp, sp2, sp3 orbital in order to form the bond.

Thus, since there has been the presence of valence electrons in the s and p orbitals, the 2s and 2p are involved in the hybridization. Hence, option C is correct.

Learn more about valence bond theory, here:

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Answer:

0.45 g

Explanation:

Step 1: Given data

Step 2: Calculate the moles of methionine (n)

We will use the following expression.

n = C × V

n = 150 × 10⁻³ mol/L × 20 × 10⁻³ L

n = 3.0 × 10⁻³ mol

Step 3: Calculate the mass of methionine (m)

We will use the following expression.

m = n × M

m = 3.0 × 10⁻³ mol × 149.21 g/mol

m = 0.45 g

Answer:

1. λ = 806nm

2. E = 2.6504 × 10^-28J

3. a) f = 1.167 × 10^15 Hz

b) E = 7.73 × 10^-19J

Explanation:

1) The wavelength denoted by λ can be calculated using the formula:

λ = v / f

Where;

v = speed of light (3×10^8m/s)

f = frequency of light (Hz)

λ = 3 × 10^8/3.72 x 1014

λ = 0.80645 × 10^(8-14)

λ = 0.80645 × 10^-6

λ = 8.06 × 10^-7m

λ = 806nm

2) The energy (J) of a photon is calculated thus;

E = hf

Where;

h = Planck's constant (6.626 × 10^-34J/s)

f = frequency (4.00x10^5/s)

E = 6.626 × 10^-34 × 4.00x10^5

E = 26.504 × 10^(-34+5)

E = 26.504 × 10^-29

E = 2.6504 × 10^-28J

3. λ = v / f

2.57x10^-7 = 3 × 10^8 ÷ f

f = 3 × 10^8/2.57x10^-7

f = 1.167 × 10^(8+7)

f = 1.167 × 10^15 Hz

b) E = hf

E = 6.626 × 10^-34 × 1.167 × 10^15

E = 7.7325 × 10^(-34+15)

E = 7.73 × 10^-19J

The final temperature = 36 °C

The balanced combustion reaction for C₆H₆

2C₆H₆(l)+15O₂(g)⇒ 12CO₂(g)+6H₂O(l)  +6542 kJ

MW C₆H₆ : 78.11 g/mol

mol C₆H₆ :

[tex]\tt \dfrac{8.5}{78.11}=0.109[/tex]

Heat released for 2 mol C₆H₆ =6542 kJ, so for 1 mol

[tex]\tt \dfrac{0.109}{2}\times 6542=356.539~kJ/mol[/tex]

Heat transferred to water :

Q=m.c.ΔT

[tex]\tt 356.539=5.691~kg\times 4.18~kj/kg^oC\times (t_2-21)\\\\t_2-21=15\rightarrow t_2=36^oC[/tex]

Answer:

please brainlist answer

Explanation:

The addition of K 3 Fe(CN) 6 to a solution causes the formation of a deep blue precipitate which indicates that iron(II) ions are present.

The conclusive test for iron(II) ions is the test by the use of potassium hexacyanoferrate III solution.

In qualitative analysis certain reagents are used to test for the presence of certain cations or anions. Those reagents react in a certain way with those reagents. Usually, a positive test may involve a color change, formation of a precipitate or evolution of a gas.

In the case of iron(II) ions, potassium hexacyanoferrate III solution is used in the conclusive qualitative test for the ion. A positive test involves the appearance of a deep blue precipitate.

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Answer:hi

Explanation:

Answer:

167 mL.

Explanation:

We'll begin by calculating the number of moles in 45 g of aluminum (Al). This can be obtained as follow:

Mass of Al = 45 g

Molar mass of Al = 27 g/mol

Mole of Al =?

Mole = mass /Molar mass

Mole of Al = 45/27

Mole of Al = 1.67 moles

Next, the balanced equation for the reaction. This is given below:

2Al + 3H2SO4 → Al2(SO4)3 + 3H2

From the balanced equation above,

2 moles of Al reacted with 3 moles of H2SO4.

Next, we shall determine the number of mole of H2SO4 needed to react with 45 g (i.e 1.67 moles) of Al. This can be obtained as:

From the balanced equation above,

2 moles of Al reacted with 3 moles of H2SO4.

Therefore, 1.67 moles of Al will react with = (1.67 × 3)/2 = 2.505 moles of H2SO4.

Thus 2.505 moles of H2SO4 is needed for the reaction.

Next, we shall determine the volume of H2SO4 needed for the reaction. This can be obtained as follow:

Molarity of H2SO4 = 15.0 M

Mole of H2SO4 = 2.505 moles

Volume =?

Molarity = mole /Volume

15 = 2.505 / volume

Cross multiply

15 × volume = 2.505

Divide both side by 15

Volume = 2.505/15

Volume = 0.167 L

Finally, we shall convert 0.167 L to mL. This can be obtained as follow:

1 L = 1000 mL

Therefore,

0.167 L = 0.167 L × 1000 mL / 1 L

0.167 L = 167 mL

Thus, 0.167 L is equivalent to 167 mL.

Therefore, 167 mL H2SO4 is needed for the reaction.

Answer:

Trioxocarbonate (iv) are salts derived from trioxocarbonate (iv) acid when it reacts with metals and metallic oxides. All trioxocarbonate (iv) salts of Sodium (Na), Potassium (K) and Ammonium(NH4+) are soluble while all others are insoluble.

Answer:

Mass is conserverd

Explanation:

Any chemical reaction must follow the law of conservation of mass. Meaning that mass cannot be created nor destroyed. Since all chemical reactions must follow this law, no matter what reaction happens, mass is conserved.

Answer:

Physical change because it can go back to its original form.

Explanation:

Answer: c. Water

Explanation:

Heat capacity can be defined as the physical property of the matter. It is the amount of heat which is required to produce a unit change in the temperature of the material.

Water requires more amount of energy per gram of the liquid to change its temperature as compare to any other liquid like ethanol and oil. Ethanol is a volatile liquid so it will require less heat to boil but heat capacity of oil will be more than the oil. The heat capacity of water will be the highest, and it will require more heat.

Answer:

Topographical

Explanation:

When it comes to questions such as this one, the thing that could help you the most is a dictionary. A dictionary is an alphabetically arranged listing of words that contains various information about those words, such as their definitions, examples, origin, pronunciation, etc.

The term the given definition refers to is topographical. Topography is the study of the forms and features of land surfaces. The topography of an area refers to its physical properties and terrain or their description (e.g. how they're shown on a map).

Answer:

Warm Water

Explanation:

In warm temperatures, cold-blooded animals are more active and can travel more quickly. This occurs because heat activated reactions provide energy to move muscles. In the absence of heat the animal becomes slow and sluggish. So they are usually inactive and rest when it is cold. As they do not need to feed much, they spend less time looking for food, so this life strategy works for them.

Brainliest?

Answer warm water Explanation:i have the same question

Answer:

1. molarity is = 0.1174

2. molarity is = 9.3

3. molarity is =0.009392

Explanation:

Q#1.

mass of sucrose is 14.07g

molar mass of sucrose is 342 3g/mol

so, 14.07x1/342.3 = 0.0411

now the volume is of water is 0.35

so, 0.0411/0.35 = 0.1174

Q#2.

concentration is 4.5

so, 4.5x1/1000= 0.0045

then, 0.0411/0.0045 = 9.13

Q#3.

M1M1=M2M2

molarity of the same sucrose is 0.1174

so, diluted in 40mL

and the volumetric flask is 500mL

so, 0.1174x40/500= 0.009392

Answer: pH = 10

Explanation: First solve for pOH using the equation pOH=-log[OH-] = 4

Then plug the pOH in the equation, pH + pOH =14

then solve for pH. pH =14 - 4 = 10

Answer:

pH= 10

Explanation:

The pH really depends on what your solution is.

For example, if we are assuming that the concentration of 1.0M is of a strong monoprotic acid e.g. HCl, it would be safe to assume that almost all of the 1.0M acid has dissociated into its H+ ion, and its conjugate base. Thus, the pH can be determined by taking the negative log(to base 10), of the concentration.

Inversely, if the solution is of a strong base, the pOH value would be found, assuming the steps above. This pOH value can be used to infer a pH from the formula - pH + pOH = 14 then 14 - 4 = 10

Finally, come the weak acids/bases, which follow the rules above, except as they only partially dissociate, one needs its equilibrium constant to determine its extent of ionisation, to substitute into the negative log. This also is the case for the second, and higher order dissociation of polyprotic acids e.g. H2SO4.the answer is 10

Hope it helps

Answer:

check the image

Explanation:

Answer:

The new material Emily invented allows scratches to be repaired quickly, so it would be useful on cars and other surfaces that experience a lot of wear.

Explanation:

I got this right on Plato\Edmentum

Answer:

The new material Emily invented allows scratches to be repaired quickly, so it would be useful on cars and other surfaces that experience a lot of wear.

Explanation:

Answer:

two of the above

Explanation:

cK-12 Bond Polarity

Answer:

Explanation:

The density of a substance can be found by using the formula

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

From the question we have

[tex]density = \frac{690}{750} = \frac{69}{75} = \frac{23}{25} \\ [/tex]

We have the final answer as

Hope this helps you

Answer:

C

Explanation:

Answer:

I think is A

Explanation:

Hope it helps

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b competition .

hope it helps u

Answer:

The work is -6,497.54 J

Explanation:

Work is the amount of energy transferred from one system to another by a force when a displacement occurs.

The work exchanged for a gas depends on the transformation it performs to go from the initial state to the final state.

The pressure - volume work done by a system that compresses or expands at constant pressure is given by the expression:

W= -P*ΔV

where

In this case:

Replacing:

W=  -570,459.8 Pa*0.01139 m³

Solving:

W=-6,497.54 J

The work is -6,497.54 J

Answer:

Because as the concentration is diminished, the capacity to transfer electricity is diminished as well.

Explanation:

Hello!

In this case, since electrolytes are substances that are able to conduct the electricity in aqueous media (solutions in which water is the the solvent) because they have the capacity to form ions with both positive and negative charges, due to the fact that HCl is a strong acid, we notice it is fully ionized in solution and therefore it is a strong electrolyte. However, when the concentration is diminished, we can notice that strength is diminished as well because less ions will have the capacity to transfer the electricity and therefore it'd become a poor conductor or weak electrolyte.

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