Astatine is a halogen with several isotopes that all have short half-lives. Which of the following combinations of mass number and neutrons are possible as isotopes of astatine? Choose one or more:
i) A = 211, n = 127
ii) A = 210, n = 125
iii) A = 220, n = 134
iv) A = 207, n = 122
v) A = 209, n = 124

Answer:

A

Explanation:

Answer: The molecule [tex]CH_{3}-CH_{3}[/tex] is expected to have a dipole moment of zero.

Explanation:

The product of magnitude of the charge calculated in electrostatic units is called dipole moment.

Formula for dipole moment is as follows.

Dipole moment = Charge (in esu) [tex]\times[/tex] distance (in cm)

Non-polar molecules have zero dipole moment.

For example, [tex]CH_{3}-CH_{3}[/tex] is a non-polar molecule so its dipole moment is zero.

[tex]H_{2}C=O[/tex] is a polar molecule so it will have dipole moment.

[tex]CH_{2}Cl_{2}[/tex] is a polar molecule so it will have dipole moment.

[tex]NH_{3}[/tex] has nitrogen atom as more electronegative than hydrogen atom. So, net dipole moment will be in the direction of nitrogen atom.

Thus, we can conclude that the molecule [tex]CH_{3}-CH_{3}[/tex] is expected to have a dipole moment of zero.

Answer:

Explanation:

1 Mole of Aluminum with mass 26.98g contains 6.02*10^23 atoms.

In 2.88g of Aluminum, there are 2.88/26.98*6.02*10^23 = 6.426*10^22 atoms.

Answer:

Explanation:

no of Al atoms = 2.88/26.98*6.02*10^23

= 6.426*10^22

= 6.43*10^22

Answer:

Hi so your answer is that to helping fix the climate change you have to : speak up , power your home with renewable engery , reduce water waste , dont waste food , and finally invest energy .

Explanation:

Really hope i helped , have a nice day :)

Answer:

we can reduce air pollution,which is one of the main cause of climate change.Climate change is not a hoxe if it is not attending the upcoming generations will suffer greatly.

Answer:

soy....plant protein also is found in vegtables and grain products.

The protein that is derived from the plant is soyabean. Protein-rich foods have a rich source of amino acids. Amino acids are required by the body for different cellular activities.

Proteins are present in plant-based foods and animal-based foods. In nature, the plant-based foods that are rich in proteins are soybeans, beans etc. Animal products such as dairy products, milk, and cheese are rich sources of proteins.

Animal-based foods such as eggs, meat, and fish have a good amount of protein. The proteins are made up of amino acids. Peptide bonds connect each amino acid to the next.

Proteins are necessary for the body, as cells need amino acids for both structural and functional support. Not all cells of the body synthesise all amino acids. Some essential amino acids are required by the body and can be taken from external sources such as plants.

Hence, the plant-based protein is soyabean.

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The question is incomplete; the complete question may be the following:

1) Which of the following is a protein source of plant origin?

A)egg

B) Soyabean

C)cheese

D)Milk

Answer:

2–methylbutane

Explanation:

To name the compound given above, the following must be obtained:

1. Determine the longest continuous carbon chain. This gives the parent name of the compound.

2. Determine the substituent group attached.

3. Determine the position of the substituent group by giving it the lowest possible count..

4. Combine the above to obtain the name of the compound.

With the above information, we can name the compound as follow:

1. The longest continuous carbon chain of the compound is 4. Thus, the parent name is butane.

2. The substituent group attached to the compound is methyl (–CH₃).

3. The methyl (–CH₃) group is located at carbon 2 (i.e counting from the left side).

4. The name of the compound is:

2–methylbutane

Answer:

C. To remove any source of bias in an experience

Answer:

b. 0.27 M ammonia + 0.38 M ammonium nitrate.

Explanation:

Hello there!

In this case, according to the given information, it turns out possible for us to bear to mind the fact that buffest must be prepared by using either of the following pairs:

weak acid/conjugate base

weak base/conjugate acid

So that the pH might be set constant. In such a way, since a. shows two salts, c. a strong acid with a neutral base, d, shows two acids and e. a strong base with a neutral base, we infer the correct buffer is b. 0.27 M ammonia + 0.38 M ammonium nitrate because it has a weak base (ammonia) and its conjugate acid, ammonium.

Regards!

4,032

BT electron

nSO2= 3nFe/

Answer:

tge answer is a

Explanation:

I'm smart like that

Explanation:

this is a single Replacement Reaction, so Na and Cl will form a bond.

Answer:

c it does not change the energy state

Explanation:

Answer:

Explanation:

Diels-Alder reactions are cyclo-additional reactions between conjugated dienes and a dienophile (a substituted alkene compound for example acrylic acid) to produce a ring structure of cyclohexene compounds.

From the image attached below, we will see the reaction between 2,3-dimethylbuta-1,3-diene which is a conjugated diene with acrylic acid to produce a Diel-Alder adduct as the product.  From the reaction, a single new π-bond and two σ-bonds are produced.

Characteristic properties are used because the sample size and the shape of the substance does not matter.

Explanation:

3 The questions refer to the substances in the table.

Melting point/°C

Boiling point/°C

A

-259

-253

Explanation:

2. [tex]2C_2H_6 + 7O_2 \rightarrow 4CO_2 + 6H_2O[/tex]

First, we need to find the number of moles of [tex]CO_2[/tex] at 300K and 1.5 atm using the ideal gas law:

[tex]n= \dfrac{PV}{RT}= \dfrac{(1.5\:\text {atm})(33\:L)}{(0.082\:\text{L-atm/mol-K})(300K)}[/tex]

[tex]=2.0\:\text{mol}\:CO_2[/tex]

Now use the molar ratios to find the number of moles of ethane to produce this much [tex]CO_2[/tex].

[tex]2.0\:\text{mol}\:CO_2 \times \left(\dfrac{2\:\text{mol}\:C_2H_6}{4\:\text{mol}\:CO_2}\right)[/tex]

[tex]=1.0\:\text{mol}\:C_2H_6[/tex]

Finally, convert this amount to grams using its molar mass:

[tex]1.0\:\text {mol}\:C_2H_6 \times \left(\dfrac{30.07\:\text g\:C_2H_6}{1\:\text{mol}\:C_2H_6} \right)[/tex]

[tex]=30.1\:g\:C_2H_6[/tex]

3. [tex]3Zn + 2H_3PO_4 \rightarrow 3H_2 + Zn_3(PO_4)_2[/tex]

Convert 75 g Zn into moles:

[tex]75\:\text g\:Zn \times \left(\dfrac{65.38\:\text g\:Zn}{1\:\text{mol}\:Zn}\right)=1.1\:\text{mol}\:Zn[/tex]

Then use the molar ratios to find the amount of H2 produced.

[tex]1.1\:\text{mol}\:Zn \times \left(\dfrac{3\:\text{mol}\:H_2}{3\:\text{mol}\:Zn}\right)=1.1\:\text{mol}\:H_2[/tex]

Now use the ideal gas law [tex]PV=nRT[/tex] to find the volume of H2 produced at 23°C and 4 atm:

[tex]V= \dfrac{nRT}{P}= \dfrac{(1.1\:\text{mol}\:H_2)(0.082\:\text{L-atm/mol-K})(296K)}{4\:\text{atm}}[/tex]

[tex]=8.9\:\text L\:H_2[/tex]

Answer:

Explanation:

The pH of a solution can be found by using the formula

[tex]pH = - log [ { H_3O}^{+}][/tex]

From the question we have

[tex]ph = - log(7.8 \times {10}^{ - 13} ) \\ = 12.1079...[/tex]

We have the final answer as

Hope this helps you

The pH of this solution with a 7.8 × 10⁻¹³ M concentration of hydronium ion is equal to: D. 12.

Given the following data:

Concentration of hydronium ion = 7.8 × 10⁻¹³ M.

pH is literally the power of hydrogen ions and it can be defined as a measure of the molar concentration of hydrogen ions in a given solution.

We would determine the pH of this solution by using this formula;

pH = -log[H⁺]

pH = -log(7.8 × 10⁻¹³).

pH = -(-12.1)

pH = 12.1 ≈ 12.

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Answer:

Part A

Ag+ is the Lewis acid and NH3 is the Lewis base.

Part B

AlBr3 is the Lewis acid and NH3 is the Lewis base.

Part C

AlCl3 is the Lewis acid and Cl− is the Lewis base.

Explanation:

A Lewis acid is any specie that accepts a lone pair of electrons. Ag^+, AlBr3 and AlCl3 all accepted lone pairs of electrons according to the three chemical reaction equations shown. Hence, they are Lewis acids.

A Lewis base donates a lone pair of electrons. They include neutral molecules having lone pair of electrons such as NH3 or negative ions such as Cl- .

Answer:

The most stable conformation of the following compound has

A. An axial methyl group and an axial ethyl group.

B. An axial methyl group and an equatorial ethyl group.

C. An axial tert-butyl group.

D. An equatorial methyl group and an equatorial ethyl group.

E. An equatorial methyl group and an axial ethyl group.

Explanation:

The most stable conformation in the cyclohexane ring is the one in which both the substituents are in the equatorial position.

Among the given options,

option D  An equatorial methyl group and an equatorial ethyl group.

When the substituents in the cyclohexane ring are in equatorial positions then, the steric repulsions will be reduced.

Answer is option D.

Answer:

hey there

Explanation:

CN- (aq) + H+ (aq) → HCN(I)

The reactants are aqueous solutions:

NaCN(aq) and HBr(aq)

When you mix these compounds you make pure HCN (I)

The molecular equation is:

NaCN(aq) + HBr(aq) → NaBr(aq) + HCN(I)

When you dissociate the reactants, you have: Nat(aq) +CN¯(aq) + H*(aq) + Br−(aq) → Nat(aq) + ->

Br (aq) + HCN(I)

Sodium bromide, it is a salt, that can also be

dissociated in the solution

To make, the net ionic equation you remove the repeated ions

CN- (aq) + H+ (aq) → HCN(I)

If you like my answer please mark as brainliest

Answer:

A) 1.3 × 10⁻⁵ mol/L

Explanation:

Step 1: Write the balanced equation for the solution of AgCl

AgCl(s) ⇄ Ag⁺(aq) + Cl⁻(aq)

Step 2: Make an ICE Chart

        AgCl(s) ⇄ Ag⁺(aq) + Cl⁻(aq)

I                           0             0

C                        +S            +S

E                          S              S

If we replace the solubility (S) in the Ksp expression, we get,

Ksp = [Ag⁺] [Cl⁻] = S × S = S²

S = √Ksp = √1.8 × 10⁻¹⁰ = 1.3 × 10⁻⁵ mol/L

Answer:

Wide melting point range - impure sample with multiple compounds

Experimental melting point is close to literature value - pure sample of a single compound

Experimental melting point is below literature value - impure sample with multiple compounds

Narrow melting point range - pure sample of a single compound

Explanation:

The melting point of substances are easily obtainable from literature such as the CRC Handbook of Physics and Chemistry.

A single pure substance is always observed to melt within a narrow temperature range. This melting temperature is always very close to the melting point recorded in literature for the pure compound.

However, an impure sample with multiple compounds will melt over a wide temperature range. We also have to recall that impurities lower the melting point of a pure substance. Hence, the experimental melting point of an impure sample with multiple compounds is always below the literature value.

Answer:

V = 364500 L, 476.748 yard³

Explanation:

Given that,

The dimensions of a room are 10 meters wide by 15 meters long and 8.0 ft high.

l = 10 m, b = 15 m, h = 8 ft = 2.43 m

The volume of the room is :

V = lbh

So,

V = 10×15×2.43

V = 364.5 m³

As 1 m³ = 1000 L

364.5 m³ = 364500 L

Also, 1 m³ = 1.30795 yard³

364.5 m³ = 476.748 yard³

Hence, this is the required solution.

Answer:

Explanation:

From the given information:

The structure of the triacylglyceride can be seen in the first image attached below and the products produced as the result of the reaction between Crisco and sodium hydroxide (NaOH) are Glycerol and 3-Palmitic acid as shown in the second image below.

Lastly, the purpose of the addition of ethanol is because water and oils are not miscible. Thus, ethanol has the potential to mix and dissolve in water as well as in oil on a selective partial level. This method aids in the formation of water, soap, salt, and fatty acids from the interaction between fatty acid and sodium hydroxide. As a result, ethanol improves the interaction between the water and the oil. It is less polar to water and aids in the dissolution of nonpolar fats such that sodium hydroxide may react with ethanol.

Answer:

NF3< H2S< H2O< He

Explanation:

The average speed of a gas depends on the relative molecular mass of the gas. Lighter gases have a greater average speed and move faster than heavier gases.

Hence, we need to arrange these gases listed in the question in order of decreasing molecular mass in order to obtain the order of increasing Urms assuming equivalent amounts and all gases are at the same temperature and pressure.

Hence; NF3< H2S< H2O< He

Answer:

Below

Explanation:

Got it right

Check the periodic table, then click electrons

Answer:

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Explanation: