Carbon-14, which is present in all living tissue, radioactively decays via a first-order process. A one-gram sample of wood taken from a living tree gives a rate for carbon-14 decay of 13.6 counts per minute. If the half-life for carbon-14 is 5720 years, how old is a wood sample that gives a rate for carbon-14 decay of 7.9 counts per minute?
A. 5.3 x 102 yr.B. 7.6 x 102 yr.C. 1.1 x 103 yr.D. 9.5 x 103 yr.

Answer: it is b

Explanation:

The total volume of gas present (in L) : 14.04 L

Reaction(balanced) :

C₂H₅OH(g) + 3O₂(g) → 2CO₂(g) + 3H₂O(l)

mol C₂H₅OH(MW=46,07 g/mol) :

[tex]\tt \dfrac{1.86}{46.07}=0.04[/tex]

mol O₂(MW=32 g/mol) :

[tex]\tt \dfrac{10}{16}=0.625[/tex]

Limiting reactant :

[tex]\tt \dfrac{0.04}{1}\div \dfrac{0.625}{3}=0.04\div 0.21\rightarrow C_2H_5OH~limiting~reactant[/tex]

mol CO₂ =

[tex]\tt \dfrac{2}{1}\times 0.04=0.08[/tex]

mol O₂(unreacted) :

[tex]\tt 0.625-(3\times 0.04)=0.505[/tex]

Conditions at T 25 ° C and P 1 atm are stated by RTP (Room Temperature and Pressure). Vm(molar volume) in this condition = 24 liters / mol

Total volume of gas :

volume O₂+volume CO₂ =

[tex]\tt 0.505\times 24+0.08\times 24=12.12+1.92=14.04~L[/tex]

Answer:

¹⁰₄Be —> ¹⁰₃Li + ⁰₋₁β

Explanation:

To know which equation is unbalanced, we shall compare the mass number and atomic number of the reactant and product together. This is illustrated below:

¹²¹₅₀Sn —> ⁰₋₁β + ¹²¹₅₁Sb

121 = 0 + 121

121 = 121

50 = –1 + 51

50 = 51

Thus the above equation is balanced

¹⁹⁰₇₈Pt —> ¹⁸⁶₇₆Os + ⁴₂α

190 = 186 + 4

190 = 190

78 = 76 + 2

78 = 78

Thus, the above equation is balanced

¹⁰₄Be —> ¹⁰₃Li + ⁰₋₁β

10 = 10 + 0

10 = 10

4 = 3 + (–1)

4 = 3 – 1

4 = 2

Thus, the above equation is unbalanced.

²³⁸₉₂U —> ⁴₂α + ²³⁴₉₀Th

238 = 4 + 234

238 = 238

92 = 2 + 90

92 = 92

Thus, the above equation is balanced.

From the illustrations made above, only ¹⁰₄Be —> ¹⁰₃Li + ⁰₋₁β

Is unbalanced.

Answer:

Most aren't able to take in carbon dioxide gas from the air or produce any oxygen.

Explanation:

science bro

Answer:

In general, metal and nonmetals combine to form ionic compounds

Explanation:

The answer would be metals :)

Answer:

the answer is pH of 7 I don't no Hydrochloric hijinx work

The equation pH = -log [H+], the pH of a solution with a hydrogen ion concentration is 5. Hence option c is correct.

Solution is defined as a continuous variation of two or more substances in their relative proportions up to what is known as the limit of solubility. Light beams do not disperse in the presence of a solution. In contrast, a suspension of particles might result in Tyndall or Rayleigh scattering. The amount of heat that is released or absorbed during the dissolving process is known as the enthalpy change of solution.

pH is defined as a measurement of how basic or acidic aqueous or other liquid solutions are. A solution's pH is a significant indicator of its chemical composition. The pH can affect how readily available nutrients are, how biological processes work, how bacteria behave, and how chemicals behave.

pH = -log[H+]

pH = -log[1.0 x 10⁻⁵]

pH = 5

Thus, the equation pH = -log [H+], the pH of a solution with a hydrogen ion concentration is 5. Hence option c is correct.

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Answer:

Masses in atomic mass units for the HD molecule by approximating the masses H and D with their mass numbers is explained below in complete detail.

Explanation:

Two volumes M1 and M2 are located on a rigid weightless rod in a rigid rotor position. Energy in a rigid rotator example: E = BJ(J+1) where, B = h/8pi2Ic, B is rotational regular, I is moment of inertia = ur2 where u is decreased mass = m1m2/m1+m2.

FOR HD MOLECULE: mass, u = mass of H*mass of D/mass of H + D. Atomic mass unit =1.67*10^-27 kg. So, u = 1*1.67*10-24 * 2*1.67*10-24 / 1.67*10-24+2*1.67*10-24 = 1.67*10-24*2/3 = 1.11*10-24 g.

Answer:

B

Explanation:

Gravitational pull is stronger when the person is closer to the planet.

The gravitational force is the fundamental force of the universe. Here the astronaut at position B will experience a stronger gravitational pull as compared to the astronaut at position A.

The gravitational force is defined as the force of attraction between any two bodies is directly proportional to the product of their masses and is inversely proportional to the square of the distance among them.

F = G m₁m₂ / r²

The gravitational force decreases with the increase in the distance. So here distance of astronaut at position B which is closer to the planet experience greater gravitational pull.

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Answer:

D. OH⁻ + H⁺ → H2O.

Explanation:

Hello!

In this case, since this problem provides the complete ionic equation by which the neutralization reaction between sodium hydroxide and sodium chloride is carried out:

[tex]Na^+(aq)+OH^-(aq)+H^+(aq)+Cl^-(aq)\rightarrow Na^+(aq)+Cl^+(aq)+H_2O(l)[/tex]

Thus, since sodium and chloride ions are the spectator ones, as they are at both reactants and products, they can be cancelled out to obtain the net ionic equation as shown below:

[tex]OH^-(aq)+H^+(aq)\rightarrow H_2O(l)[/tex]

Therefore, the answer would be D. OH⁻ + H⁺ → H2O.

Best regards!

Answer:

Lock her in the bathroom

Explanation:

Answer:

Ayoo

Explanation:

Answer:

Yeasts reproduce asexually by a process called budding (see Figure 8.2. 1 and Figure 8.2. 6). A bud is formed on the outer surface of the parent cell as the nucleus divides.

Explanation:

Answer:

Yes the given equation is balanced.

Explanation:

Chemical equation:

Fe + O₂       →     Fe₂O₃

Balanced chemical equation:

4Fe + 3O₂       →     2Fe₂O₃

There are four iron and six oxygen atoms on both side of equation thus the given equation is balanced.

The given reaction also follow the law of conservation of mass.

According to the law of conservation mass, mass can neither be created nor destroyed in a chemical equation.

This law was given by French chemist  Antoine Lavoisier in 1789. According to this law mass of reactant and mass of product must be equal, because masses are not created or destroyed in a chemical reaction.

This reaction is synthesis reaction:

Synthesis reaction:

It is the reaction in which two or more simple substance react to give one or more complex product.

A + B      →   AB

Answer:

8 protons, 10 electrons.

Explanation:

the -2 charge adds 2 electrons–hence, you have 10 electrons while protons remain at 8.

Answer:

Following are the solution to this question:

Explanation:

Following are the lewis structure of the [tex]NH_2^{-}[/tex]:

In the given element two H and one N are used, in which N has 5 valance electrons, and one H has 1 valence which is equal to 2 electrons valance. So, the graph for the given element is defined in the attached file.

The Lewis structure for the amide anion can be shown as in the given figure.

Lewis structures, also known as Lewis dot formulas, are diagrams that show the bonding between atoms of a molecule, as well as the lone pairs of electrons that may exist in the molecule.

In the given element two H and one N are used, in which N has 5 valance electrons, and one H has 1 valence which is equal to 2 electrons valance. The Lewis structure for the amide anion can be shown

Hence, this is the required answer.

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Answer:

Solution-a liquid mixture in which the minor component (the solute) is uniformly distributed within the major component (the solvent).

solvent- able to dissolve other substances.

solute- the minor component in a solution, dissolved in the solvent.

colloid- a homogeneous noncrystalline substance consisting of large molecules or ultramicroscopic particles of one substance dispersed through a second substance. Colloids include gels, sols, and emulsions; the particles do not settle, and cannot be separated out by ordinary filtering or centrifuging like those in a suspension.

suspension- is a heterogeneous mixture that contains solid particles sufficiently large for sedimentation.

Explanation:

Answer:

B. Influenza affects one system, but multiple systems must interact in order to restore homeostasis.

Explanation:

According to the CDC, influenza is a respiratory illness caused by the flu virus of which some symptoms include cough, sore throat, muscle aches, and vomiting.

The statement that represents a reasonable claim about the effects of the flu virus on the body’s ability to maintain homeostasis is that it affects one system which is the RESPIRATORY SYSTEM but multiple systems must intervene in other to maintain homeostatis.

*Homeostatis is the unique way a human body or organism stabilises its internal state despite the changes on the external.

Answer:

NaOH + HCl = NaCl + H2O

(3.612 moles of HCl) x (1/1) x (39.9971 g/mol) = 144.5 grams

So answer B.

Explanation:

NaOH + HCl = NaCl + H2O

(3.612 moles of HCl) x (1/1) x (39.9971 g/mol) = 144.5 grams

To solve such this we must know the concept of double displacement reaction. Therefore, 144.48g sodium hydroxide will neutralize completely 3.612 moles of HCl.

Chemical reaction is a process in which two or more than two molecules collide in right orientation and energy to form a new chemical compound. The mass of the overall reaction should be conserved. There are so many types of chemical reaction reaction like combination reaction, double displacement reaction.

The balanced reaction is

NaOH + HCl = NaCl + H2O

To neutralize completely 3.612 moles of HCl, 3.612 moles of NaOH  is required.

mass of  NaOH =Mole× Molar mass of NaOH

mass of NaOH=3.612× 40 g/mol

mass of NaOH=144.48g

Therefore, 144.48g sodium hydroxide will neutralize completely 3.612 moles of HCl.

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Answer: D) Eight

Just pretend this part doesn't exist nope nothing to see here the answer is correct on edge2020 I swear on my brainly points

Answer:

d

Explanation:

Answer:

Explanation:

C₂E₁₀H₁₂  = 144

molecular weight of given compound

= 2 x 12 + 10 x E + 12 x 1 = 144 ( atomic weight of C = 12 , H = 1 , E = E )

24 + 10 E + 12 = 144

10 E = 108

E = 10.8

Atomic mass of E = 10.8 u .

Answer:

Explanation:

There are 2.

Answer:

[tex]m_{Fe_2O_3}=160.41gFe_2O_3[/tex]

Explanation:

Hello!

In this case, since the reaction between aluminum and iron (III) oxide is:

[tex]2Al+Fe_2O_3\rightarrow Al_2O_3+2Fe[/tex]

In such way, since there is 2:1 mole ratio between aluminum (atomic mass = 26.98 g/mol) and iron (III) oxide (molar mass = 159.70 g/mol), we'll be able to compute the mass of the required reactant as shown below:

[tex]m_{Fe_2O_3}=54.2gAl*\frac{1molAl}{26.98gAl}* \frac{1molFe_2O_3}{2molAl}*\frac{159.70gFe_2O_3}{1molFe_2O_3}\\\\m_{Fe_2O_3}=160.41gFe_2O_3[/tex]

Best regards!

Answer:

Ionization Energy

Explanation:

Factors such as nuclear charge and distance of electrons to the nucleus

affect the attractive force between the nucleus of an atom and its valence

electrons.

The closer the electron to the nucleus the higher the attractive force.

Nucleus possesses an attractive force for stability which is stronger in

electrons in close proximity with it.

We should also note that the higher the nuclear charge, the stronger the

attractive force and vice versa.

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Answer:

The molecular weight is [tex]Z = 111.2 \ g/mol[/tex]

Explanation:

From the question we are told that

   The mass of the sample is  [tex]m = 0.98 \ g[/tex]

    The temperature is  [tex]T = 348 K[/tex]

    The volume which the gas occupied is  [tex]V = 265 \ ml = 265 *10^{-3} L[/tex]

     The pressure is  [tex]P = 0.95 \ atm[/tex]

Generally from the ideal gas equation we have that

       [tex]PV = n RT[/tex]

Here n is the number of moles of the gas while the R is the gas constant with value  [tex]R = 0.0821 \ atm \cdot L \cdot mol^{-1} \cdot K^{-1}[/tex]

        [tex]n = \frac{PV}{ RT}[/tex]

=>      [tex]n = \frac{ 0.95 * 265 *10^{-3} }{ 0.0821 * 348}[/tex]

=>      [tex]n = 0.00881 \ mol[/tex]

Generally the molecular weight is mathematically represented as

          [tex]Z = \frac{m}{n}[/tex]

=>      [tex]Z = \frac{0.98 }{0.00881}[/tex]

=>      [tex]Z = 111.2 \ g/mol[/tex]

Answer:

They both have a cell wall

Explanation:

Answer:

D

Explanation:

The architectural achievement of Nebuchadnezzar II which is considered one of the Seven Wonders of the Ancient World is the Hanging Gardens of Babylon.

The Hanging Gardens were said to be a lush and elaborate terraced garden complex located in the city of Babylon, in present-day Iraq. According to ancient accounts, the gardens were built by Nebuchadnezzar II in the 6th century BCE as a gift to his wife Amytis, who missed the green hills and gardens of her homeland.

The gardens were renowned for their impressive engineering and beauty. They were designed to resemble a large artificial mountain, with ascending terraces supported by vast stone columns and arches. Each terrace was filled with a variety of plants, trees, and flowers, creating a mesmerizing display of color and fragrance.

Hence, the architectural achievement of Nebuchadnezzar II is considered one of the Seven Wonders of the Ancient World is Hanging Gardens

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Answer:

the answer is A

Answer:

Science tells us that light is the reason we are able to see objects. Without light, we wouldn't be able to process the visible world. ... The electromagnetic spectrum is the range of all types of electromagnetic radiation, including visible light, infrared light, ultraviolet light, X-rays, and gamma rays.

Explanation:

i hope this is right :)

Answer:

The Visible Spectrum Visible light is the light that we can see, and thus is the only light detectable by the human eye. White light is visible light, and it contains all the colors of the rainbow, from red to violet. The range of visible wavelengths is 400 to 700 nanometers.

Explanation: