how to find the number of neutrons

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Answer: The cathode is the electrode where reduction (gain of electrons) takes place (metal-B electrode)

Answer: The electrode where reduction occurs.

Answer:

See explanation for details

Explanation:

a) Now from the data given, recall that;

N/No = (1/2)t/t1/2

Where,

N= amount of radioactive material remaining at time t

No= Amount of radioactive material originally present

t= time taken for N amount of radioactive material to remain

t1/2= half life of radioactive material

So,

N/No = (1/2)^20,000/5730

N/No = (1/2)^3.49

N/No = 0.089

Since the fraction N/No is the fraction remaining after t years, then;

Percentage of Carbon-14 left after 20,000 years = 0.089 * 100 = 8.9%

b) From;

0.693/t1/2 = 2.303/t log No/N

Given that N = 0.42 No

Hence;

0.693/5730 = 2.303/t log (No/0.42No)

1.21 * 10^-4 = 0.87/t

t= 0.87/1.21 * 10^-4

t = 7190 years

c) Radiocarbon dating is a method of obtaining the age of an object derived from plants or animals by comparing the Carbon-14 activity of living things with that of the sample under study. Due to contamination, the age of artifacts obtained by Carbon-14 dating may yield outlying figures.

Answer:

[tex]T_{eq}=27.97\°C[/tex]

Explanation:

Hello.

In this case, for equilibrium temperature problems, it is said that the heat balance allows us to notice how the hot substance heats up the cold substance until they reach the equilibrium temperature which is a temperature that remains constant upon time. Thus, since here the hot substance is the nickel and water gains that released heat by the nickel we can write:

[tex]Q_{Zn}=-Q_{water}[/tex]

Which can be written in terms of temperatures, masses and specific heats:

[tex]m_{Zn}C_{Zn}(T_{eq}-T_{Zn})=-m_{water}C_{water}(T_{eq}-T_{water})[/tex]

Thus, solving for the equilibrium temperature we write:

[tex]T_{eq}=\frac{m_{Zn}C_{Zn}T_{Zn}+m_{water}C_{water}T_{water}}{m_{Zn}C_{Zn}+m_{water}C_{water}}[/tex]

Now, plugging in the known data, considering the mass of water 64.00-4.00=60.00 g and its initial temperature, 25.00°C, we obtain:

[tex]T_{eq}=\frac{34.10g*0.444\frac{J}{g\°C}* 77.17\°C+60.0g*4.184\frac{J}{g\°C}*25.00\°C}{34.10g*0.444\frac{J}{g\°C}+60.0g*4.184\frac{J}{g\°C}}\\\\T_{eq}=27.97\°C[/tex]

Best regards!

The final temperature of water is required.

The final temperature of water is [tex]27.97^{\circ}\text{C}[/tex].

T = Equilibrium temperature

[tex]T_n[/tex] = Temperature of nickel = [tex](77.17^{\circ}\text{C}+273.15)\ \text{K}[/tex]

[tex]T_w[/tex] = Temperature of water = [tex](25^{\circ}\text{C}+273.15)\ \text{K}[/tex]

[tex]c_n[/tex] = Specific heat of nickel = [tex]0.444\ \text{J/g}^{\circ}\text{C}[/tex]

[tex]c_w[/tex] = Specific heat of water = [tex]4.184\ \text{J/g}^{\circ}\text{C}[/tex]

[tex]m_n[/tex] = Mass of nickel = 34.1 g

[tex]m_w[/tex] = Mass of water = 60 g

The heat balance of the system is given by

[tex]m_wc_w(T-T_w)=m_nc_n(T_n-T)\\\Rightarrow m_wc_wT-m_wc_wT_w=m_nc_nT_n-m_nc_nT\\\Rightarrow T=\dfrac{m_nc_nT_n+m_wc_wT_w}{m_wc_w+m_nc_n}\\\Rightarrow  T=\dfrac{34.1\times 0.444\times 350.32+60\times 4.184\times 298.15}{60\times 4.184+34.1\times 0.444}\\\Rightarrow T=301.12\ \text{K}=301.12-273.15\\\Rightarrow T=27.97^{\circ}\text{C}[/tex]

The final temperature of water is [tex]27.97^{\circ}\text{C}[/tex].

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Answer:

A covalent bond is a chemical bond that involves the sharing of electron pairs between atoms. These electron pairs are known as shared pairs or bonding pairs, and the stable balance of attractive and repulsive forces between atoms, when they share electrons, is known as covalent bonding.

Explanation:

More than one pair of electrons can be shared between atoms to form double or triple covalent bonds. Unlike ionic bonds, covalent bonds are often formed between atoms where one of the atoms cannot easily attain a noble gas electron shell configuration through the loss or gain of one or two electrons.

The total mass of the products is 40 grams (Option C).

In 1789, Antoine Lavoisier discovered that mass is neither created nor destroyed in chemical reactions. This is now known as Lavoisier's law of conservation of mass. In other terms, the sum of the masses of the reactants is equal to the sum of the masses of the products. So, in this case, the total mass of the products must be 40 grams as well.

The total mass of the products is 40 grams.

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Answer:

Hail pallets forms inside of cumulonimbus clouds

Explanation:

Answer: cumulonimbus hope it helps pls stay safe

Answer:

The answer is

C. Graph A

Answer:

Graph A

Explanation:

:)

Answer:

Explanation:

Sn (Z = 50 )

Electronic configuration = [Kr] 4d¹⁰5s²5p²

= 1s²2s²p⁶3s²3p⁶3d¹⁰4s²4p⁶4d¹⁰5s²5p²

So , total number of electrons in d orbital = 10 + 10 = 20 .

Answer:

147.6 mL .

Explanation:

sodium carbonate , Na₂CO₃

Molecular weight = 106

3.55 gm of sodium carbonate = 3.55 / 106

= .0335 moles

Let the volume of litre required = V

V litre of .227 M solution will contain

V x .227 moles of sodium carbonate . So

V x .227 = .0335

V = .1476 L

= 147.6 mL .

Answer:

1.0979g of Na2CO3

0.8471g of NaHCO3

Explanation:

NaHCO3 and Na2CO3 reacts with HCl as follows:

NaHCO3 + HCl → NaCl + H2O + CO2

Na2CO3 + 2HCl → 2NaCl + H2O + CO2

Moles of HCl required were:

0.03531L * (0.8724mol / L) = 0.03080 moles of HCl

With this information we can write 2 equations:

1.9450g = X + Y (1)

X is the mass of NaHCO3 and Y is mass of Na2CO3

Also we can write:

0.03080 moles = X/84 + 2Y/106 (2)

Where 84 is molar mass of NaHCO3 and 106 is molar mass of Na2CO3, 2 is due the reaction (2 moles of HCl react per mole of Na2CO3)

Replacing (1) in (2):

0.03080 moles = (1.9450-Y)/84 + 2Y/106

0.03080 = 0.023155 - Y/84 + Y/53

0.007645 = 0.00696316Y

Y = 1.0979g of Na2CO3

And mass of NaHCO3 =

1.9450g - 1.0979g =

0.8471g of NaHCO3

Answer: 3

Explanation:

It speed up the molecules to get them to bent and move instead of staying solid

Answer:

c

Explanation:

When enough heat energy is transferred to a metal, the molecules vibrate quickly enough so that the solid metal starts to change shape.

Answer:

How hot or cold the substance is

Explanation:

You can do a lot with just the temperature of a substance. Chemists can use this to identify the substance because of the temperature at which it melts. They can then find out how long it took to melt, which can also help.

Answer:c how hot or cold

Explanation:

Answer:

a = 1, b = 11, c = 7, d = 8

Explanation:

aC7H16 + bO2 ------> cCO2 + dH2O

1 C7H16 + 11 O2 ------> 7 CO2 + 8H2O

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Answer: the slope of the calibration curve is - 0.0295

Explanation:

as things are not under standard conditions that is;  1M of each reactants at T = 25°C and P = 1 atm; therefore we will use the Nernst Equation.

E = a × pNi + b

a is the slope

pNi = -log [Ni²⁺] = log 1/[Ni²⁺]

therefore the Half reaction;

Ni²⁺ (aq) + 2e⁻ = Ni (s)

here; E = E₀ + RT/zF ln[Ni²⁺]

we know that;

gas constant R = (8.31 J/mol-K)

absolute temperature T =25°C =  298 K

number of moles of electrons transferred by the cell's reaction z  = 2

F is Faraday constant, = 9.64853399(24)×10⁴ C mol−1

E₀ = b

RT/zF ln[Ni²⁺] = alog 1/[Ni²⁺]

Logx = Ln x / Ln 10 = Ln (x/2.3)

so

a = (RT/zF ln[Ni²⁺])/log 1/[Ni²⁺]

= (RT/zF ln[Ni²⁺]) / ((ln 1/[Ni²⁺]) / 2.3)  

= (2.3RT/zF ln[Ni²⁺]) / (ln 1/[Ni²⁺])

= (2.3RT/zF ln[Ni²⁺]) / (-ln [Ni²⁺])

= -2.3RT/zF

so we substitute

= (-2.3 × 8.31 ×298 ) / (2 × 9.64853399(24) × 10⁴)

= - 0.0295

therefore the slope of the calibration curve is - 0.0295

Answer:

Explanation:

white ring of NH₄X is formed . Here X is Cl and

NH₄X is NH₄Cl ( ammonium chloride )

The reaction is as follows

NH₃ + HCl = NH₄Cl ( white fume )

The acid that reacts with ammonia has been Hydrochloric acid (HCl), and the element X in the acid has been Chlorine (Cl).

The ammonia has been the gas with the pungent smell. It has been the compound with the dihybrid element used for the production of various nitrogen compounds.

The reaction of Ammonia with acid results in the formation of ammonium ions. The ions on reacting with the basic part of the acid, form the salt and give the product.

The white ring with the reaction of ammonia has been formed of the ammonium chloride. Thus the acid that reacts with ammonia has been Hydrochloric acid (HCl), and the element X in the acid has been Chlorine (Cl).

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Answer:

Answer is the number of the c

Answer:

Yes

Explanation:

yes, this is in every chemical reaction (except nuclear reaction) and Is known as "law of conservation of mass"

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Answer:

0.186M

Explanation:

First, we need to obtain the moles of nitric acid that are given for each solution. Then, we need to divide these moles in total volume (120mL + 20mL = 140mL = 0.140L) to obtain molarity:

Moles Nitric acid:

0.0200L * (0.100mol / L) = 0.00200 moles

0.120L * (0.200mol / L)= 0.02400 moles

Total moles: 0.02400moles + 0.00200moles = 0.026 moles of nitric acid

Molarity: 0.026 moles / 0.140L

Answer:

0.0956 M

Explanation:

Step 1: Calculate the moles corresponding to 6.25 g of barium nitrate (solute)

The molar mass of barium nitrate is 261.34 g/mol.

6.25 g × 1 mol/261.34 g = 0.0239 mol

Step 2: Convert the volume of solution to liters

We will use the conversion factor 1 L = 1000 mL.

250 mL × 1 L/1000 mL = 0.250 L

Step 3: Calculate the molarity of the solution

The molarity is equal to the moles of solute divided by the liters of solution.

M = 0.0239 mol / 0.250 L = 0.0956 M

Answer:

your answer would be false.

Explanation:

prevailing winds blow east-west rather than north-south.

11.02g

Explanation:

mole ratio between H2SO4 and water is 1:2

mole of H2SO4 is 0.306

then the mole of water is 0.612

finally the mole of water is multiplied by 18, the molar mass to get 11.02 g of water

Answer:

The objects must be different temperatures and they must be in contact.

Explanation:

For conduction to take place between two objects, they must be in contact with one another and at different temperatures.

Answer:

The objects must be different temperatures and they must be in contact.

Explanation:

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HOPE THIS HELPS!!!

Answer:

12-6=6

the answer is A)6

Answer:

it is the letter D

Explanation:

Considering the definition of wavelength, the correct answer is option D. You can see that "d" represents the distance between two consecutive highs, and then the wave repeats. In this way the definition of wavelength is fulfilled.

In a periodic wave, that is, for the type of wave that repeats with exactly the same shape every given time interval, the wavelength is the physical distance between two points from which the wave repeats.

That is, the wavelength is its spatial period, that is, the distance at which the waveform repeats itself. Normally, two consecutive points that have the same phase are considered: two maximums, two minimums, two zero crossings (in the same direction).

In summary, the wavelength is the actual distance that a disturbance can travel in a given time interval, the quas between two consecutive maxima with respect to the physical property of the wave.

Considering the definition of wavelength, the correct answer is option D. You can see that "d" represents the distance between two consecutive highs, and then the wave repeats. In this way the definition of wavelength is fulfilled.

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Answer:

b option is the answer.

Answer:

-2

__________________________________________________________

How many electrons does Oxygen need:

We know that oxygen has an electric configuration of:

2 , 6     [8 electrons]

From the octet rule, we know that all elements try to get to the electronic configuration of the nearest noble gas

In the case of Oxygen, the nearest noble gas is Neon with the electronic configuration:

2 , 8     [10 electrons]

From the above, we can see that oxygen needs 2 more electrons in order to attain the nearest noble gas configuration

What will be the Charge on the ion?:

We know that electrons are negatively charged

Once oxygen gains 2 electrons to attain noble gas configuration, it will have 2 more electrons than it should have

So, the charge on the ion will be -2 since there are 2 extra electrons and both of the electrons contribute a negative charge

Hence, the charge is -2

Answer:

Boron is Nonmetal

Explanation:

hope it's helped

Answer:

2.14 moles of H₂O₂ are required

Explanation:

Given data:

Number of moles of H₂O₂ required = ?

Number of moles of N₂H₄ available = 1.07 mol

Solution:

Chemical equation:

N₂H₄  +   2H₂O₂       →   N₂ +  4H₂O

now we will compare the moles of H₂O₂ and N₂H₄

                          N₂H₄     :      H₂O₂  

                            1           :        2

                            1.07      :         2×1.07 = 2.14 mol

Answer:

random internal motion of atoms and molecule

Explanation:

The primary cause of diffusion is the random internal motion of atoms and molecules.

Randomness of atoms and molecules results in diffusion.

Answer:

random internal of motion of atoms and molecules

Explanation:

took assignment on odyssey ware

Answer:

80.2L

Explanation:

Given parameters:

Initial volume of oxygen = 47.2L

Initial pressure of oxygen = 1240torr

Final pressure  = 730torr

Unknown:

Final volume  = ?

Solution:

To solve this problem, we apply the Boyle's law proposed by Robert Boyle. It states that "the volume of a fixed mass of a gas varies inversely as the pressure changes if the temperature is constant".

Mathematically;

             P₁V₁ = P₂V₂

P and V are pressure and volume

1 and 2 are initial and final states

              1240 x 47.2  = 730 x V₂  

                  V₂  = 80.2L