The radioactivity due to carbon-14 measured in a piece of a wood from an ancient site was found to produce 20 counts per minute from a given sample, whereas the same amount of carbon from a piece of living wood produced 160 counts per minute. The half-life of carbon-14, a beta emitter, is 5730 y. The age of the artifact is closest to

Answer:

a. 7278 K

b. Kc = 4.542 × 10⁻³¹

Explanation:

a.

The reaction is spontaneous when ΔG° < 0. We can calculate ΔG° using the following expression.

ΔG° = ΔH° - T × ΔS°

Then, the reaction will be spontaneous when,

ΔH° - T × ΔS° < 0

T > ΔH°/ΔS

T > (180.5 × 10³ J/mol)/(24.80J/mol⋅K)

T > 7278 K

b.

First, we will calculate ΔG° at 25 °C (298 K)

ΔG° = ΔH° - T × ΔS°

ΔG° = (180.5 × 10³ J/mol) - 298 K × (24.80J/mol⋅K) = 1.731 × 10⁵ J/mol

Then, we will calculate the equilibrium constant (Kc) using the following expression.

ΔG° = - R × T × ln Kc

-ΔG°/R × T =  ln Kc

-(1.731 × 10⁵ J/mol)/(8.314 J/mol.K) × 298 K =  ln Kc

Kc = 4.542 × 10⁻³¹

Explanation:

here are the answers for your questions

I basically converted the given grams to moles, and then multiplied that by the product-to-reactant ratio in the equation, and then convert that to grams

Answer:

Explanation:

1.

The reaction can be represented by the equation: Zn + 2 HCl -> ZnCl2 + H2

From the equation, molar ratio of Zn and ZnCl2 is 1:1.

Molar mass of Zn = 65.38

Molar mass of ZnCl2 = 65.38 + 35.45*2 = 136.28

So 6.0 grams of Zn will produce 6 / 65.38 * 136.28 = 12.5 grams

2.

As the only other product is copper (II) oxide, the reaction can be represented by the equation: CuCO3 -> CuO + CO2

From the equation, molar ratio of CuCO3 and CuO is 1:1.

Molar mass of CuCO3 = 123.55

Molar mass of CuO = 79.55

So 45.0 grams of CuCO3 will produce 45 / 123.55 * 79.55 = 28.96 grams

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Answer:

If you contact water with a gas at a certain temperature and (partial) pressure, the concentration of the gas in the water will reach an equilibrium ('saturation') according to Henry's law.

Explanation:

This means: if you increase the pressure (e.g. by keeping the vial closed), the CO2 concentration will increase. So it simply depends what concentration you need for your assay: 'CO2-saturated' water at low pressure or 'CO2-saturated' water at high pressure.

Answer:

1.59 M

Explanation:

What is the concentration (M) of CH₃OH a solution prepared by dissolving 11.7 g of CH₃OH sufficient water to give exactly 230 mL of solution?

Step 1: Given data

Step 2: Calculate the moles corresponding to 11.7 g of CH₃OH

The molar mass of CH₃OH is 32.04 g/mol.

11.7 g × 1 mol/32.04 g = 0.365 mol

Step 3: Calculate the molarity of the solution

M = moles of solute / liters of solution

M = 0.365 mol / 0.230 L = 1.59 M

Answer:

The activation energy

Explanation:

The activation energy is the energy hump that lies between reactants and products. It is the energy barrier that reactants must cross before they are converted into products.

Based on the collision theory, only particles that possess the activation energy are able to collide in such a way that leads to reaction.

Collision of particles having an energy content less than the activation energy of the reaction merely leads to elastic collision between such particles.

Answer:

Explanation:

2Fe(s) + 3Pb(NO₃)₂(aq) = 3Pb(s) + 2Fe(NO₃)₃(aq)

Half ionic reactions

2Fe(s) = 2Fe⁺³ + 6e

3Pb⁺² + 6e = 3 Pb(s)

In the first reaction Fe is oxidised to Fe⁺³ because its oxidation number increases from zero to + 3 .

In the second reaction , Pb⁺² is reduced to Pb (s) because its oxidation number is reduced from + 2 to zero.

Answer:

γ−Hydrogen is easily replacable during bromination reaction in presence of light , because Allylic substitution is being preferred.

Explanation:

that's all

γ−Hydrogen is easily replacable during bromination reaction in presence of light , because Allylic substitution is being preferred.

Answer:

is C the Ch because is look 99% the answer pls don't report if I'm wrong it took me a long time to answer it

Answer:

Do you know the formula¿?

Answer:

True

Explanation:

Explanation:

Normality is one of the concentration terms.

It is expressed as:

[tex]N=\frac{mass of the substance}{equivalent mass}* \frac{1}{volume of solution in L.}[/tex]

The volume of the solution is 425 mL.

Mass of sulfuric acid given is:

[tex]mass=volume * purity* density\\ = 75 mL * 0.966 * 1.83 g/mL\\\\=132.5 grams\\[/tex]

The equivalent mass of sulfuric acid is 49.0g/equivalents

Hence, the normality of the given solution is:

[tex]N=\frac{132.5g}{49.0g/equi.} *\frac{1000}{425mL} \\Normality=6.36N[/tex]

Answer is: 6.36N.

Answer:

It is a Biological Molecule

Answer:

the entropy change for the system when 1.58 moles of CaCO3(s) react at standard conditions is 253.748 J/K

Explanation:

Given the data in the question;

CaCO₃(s)       →     CaO(s)     +     CO₂(g)  

1.58 moles        1.58 moles     1.58 moles

Since 1 mole of CaCO₃ gives 1 mole of CaO and 1 mole of CO₂

Thus, 1.58 mole of CaCO₃ gives 1.58 moles of CaO and 1.58 moles of CO₂.

Now,

At 298 K, standard entropy values are;

ΔS° ( CaCO₃ ) = 92.9 J/mol.K

ΔS° ( CaO )     = 39.8 J/mol.K

ΔS° ( CO₂ )      = 213.7 J/mol.K

So,

ΔS°[tex]_{system[/tex] = ∑ΔS°( product ) - ∑ΔS°( reactant )

ΔS°[tex]_{system[/tex] = [ ΔS°(CaO) + ΔS°( CO₂ ) ] - ΔS°( CaCO₃ )

we substitute

ΔS°[tex]_{system[/tex] = [ 39.8 J/mol.K + 213.7 J/mol.K ] - 92.9 J/mol.K

ΔS°[tex]_{system[/tex] = 160.6 J/mol.K

i.e, for 1 mol CaCO₃, ΔS°[tex]_{system[/tex] = 160.6 J/mol.K

Now, for 1.58 mol CaCO₃,

ΔS°[tex]_{system[/tex] = 1.58 mol × 160.6 J/mol.K

ΔS°[tex]_{system[/tex] = 253.748 J/K

Therefore, the entropy change for the system when 1.58 moles of CaCO3(s) react at standard conditions is 253.748 J/K

Answer:

Hydrogen Bonding

Explanation:

Hydrogen Bonding occurs when a hydrogen atom is bonded to N, O, and F atoms.

The molecules H₂O, HF, and NH₃ all experience hydrogen bonding, which is a relatively strong IMF, causing the molecules to have stronger attraction to each other. Having a stronger attraction between molecules results in more energy required to separate them, thus these molecules will have a higher boiling point than the rest of the molecules in their group.

Answer:

Precipitation

Explanation:

Let's consider the balanced chemical equation between barium acetate and sodium carbonate to form barium carbonate and sodium acetate.

Ba(C₂H₃O₂)₂(aq) + Na₂CO₃(aq) → BaCO₃(s) + 2 NaC₂H₃O₂(aq)

Both products and reactants are salts. But, among the products, barium carbonate is solid. This allows us to classify it as a precipitation reaction.

Answer:

+5

Explanation:

Answer:

ATP hydrolase

Explanation:

Enzymes are biological catalysts which perform diverse functions in the body. Enzymes are specific in their mode of action because an enzyme fits into its substrate as a key fits into a lock.

The particular enzyme that catalyzes the breakdown of ATP to ADP is ATP hydrolase. The phosphate released by the action of this enzyme is used in the phosphorylation of other compounds thereby making them more reactive.

Explanation:

Molarity(M) of a solution is defined as the number of moles of solute(n) present in one liter of solution(V).

[tex]M=\frac{n}{V}[/tex]

The number of moles(n) can be calculated as shown below:

[tex]n=\frac{mass of solute}{molar mass of solute}[/tex]

Molar mass of dextrose is 198.17 g/mol

Molar mass of NaCl is 58.5 g/mol.

Volume of the solution =250.0mL=0.250 L

The number of moels of dextrose([tex]n_{d}[/tex]) is:

[tex]n_{d} =\frac{13.252g}{198.17g/mol} \\=0.0669mol[/tex]

The number of moles of NaCl is:

[tex]n_{NaCl} =\frac{0.686 g}{58.5g/mol} \\\\=0.01177 mol[/tex]

Thus, the molarity of dextrose is:

[tex]M_d=\frac{n_d}{0.250 L} \\=0.0669mol/0.250L\\=0.268 M[/tex]

The molarity of NaCl is:

[tex]M_Na_Cl=\frac{n_d}{0.250 L} \\\\=0.0118mol/0.250L\\\\=0.0472 M[/tex]

Answer:

The molarity of dextrose is 0.268 M.

The molarity of NaCl is 0.0472 M.

Answer:

C) Both will require the same amount because the concentrations are equal.

Explanation:

The pH of a solution is defined as:

pH = -log [H+]

This H+ is the ion that reacts with OH- (From NaOH) as follows:

H+ + OH- → H2O

When all H+ reacts, we can say the solution was neutralized.

Now, as both, the solution with the weak acid and the solution with strong acid have the same pH, we can say that their [H+] is the same. Assuming the volume of both solutions is the same:

Both will require the same amount because the concentrations are equal.

Answer:

When copper(II) chloride and sodium carbonate solutions are combined, solid copper(II) carbonate precipitates, leaving a solution of sodium chloride. Write the conventional equation, total ionic equation, and net ionic equation for this reaction.

Explanation:

The word equation for the reaction is:

Copper (II) chloride(aq) + sodium carbonate (aq) ->sodium chloride (aq) +           copper carbonate(s)

The balanced chemical equation of the reaction is:

[tex]CuCl_2(aq)+Na_2CO_3(aq)->2NaCl(aq)+CuCO_3(s)[/tex]

The complete ionic equation is:

[tex]Cu^2+(aq)+2Cl^-(aq)+2Na^+(aq)+CO_3^2^-(aq)->2Cl^-(aq)+2Na^+(aq)+CuCO_3(s)\\[/tex]

The net ionic equation is obtained from the complete ionic equation after removing the spectator ions:

[tex]Cu^2^+(aq)+CO_3^2^-(aq)->CuCO_3(s)[/tex]

Answer:

The pressure of the resulting mixture of gases will be 4.89 atm.

Explanation:

An ideal gas is a theoretical gas that is considered to be composed of randomly moving point particles that do not interact with each other. Gases in general are ideal when they are at high temperatures and low pressures.

The pressure, P, the temperature, T, and the volume, V, of an ideal gas, are related by a simple formula called the ideal gas law:  

P*V = n*R*T

where P is the gas pressure, V is the volume that occupies, T is its temperature, R is the ideal gas constant, and n is the number of moles of the gas. The universal constant of ideal gases R has the same value for all gaseous substances. The numerical value of R will depend on the units in which the other properties are worked.

In this case:

Replacing:

P* 35 L= 7 moles* 0.082 [tex]\frac{atm*L}{mol*K}[/tex] * 298 K

Solving:

[tex]P=\frac{ 7 moles* 0.082 \frac{atm*L}{mol*K} * 298 K}{35 L}[/tex]

P= 4.89 atm

The pressure of the resulting mixture of gases will be 4.89 atm.

The pressure (in atm) of the resulting mixture of the gases is 4.89 atm

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

Mole of N₂ = 3 moles

Mole of O₂ = 4 moles

Total mole = 3 + 4 = 7 moles

Volume (V) = 35 L

Temperature (T) = 25 °C = 25 + 273 = 298 K

Gas constant (R) = 0.0821 atm.L/Kmol

The pressure of the resulting mixture of the gases can be obtained by using the ideal gas equation as illustrated below:

PV = nRT

P × 35 = 7 × 0.0821 × 298

P × 35 = 171.2606

Divide both side by 35

P = 171.2606 / 35

Therefore, the pressure of the resulting mixture of the gases 4.89 atm

Learn more: https://brainly.com/question/21912477

Answer:

Following are the solution to these questions:

Explanation:

P-toluene sulfonic acid variations between Amberlyst-15

Acid p-Toluenesulfonic (PTSA)

Amberlyst 15

P-toluene and Amberlyst-15 do have the same catalytic effect in the reaction as the mechanism is defined in the attached file. The Amberlyst 15 is always considered as best, given the better future for Amberlyst 15.

Explanation:

I have no idea about this

Answer:

because electron molecule in floirine are tightly held to the nuclei dispersion force are relatively weak and in iodine they are strong

Answer:

2.05 g

Explanation:

Number of moles of salicylamide = 1.07g/137.14 g/mol = 0.0078 moles

Number of moles of NaI = 1.68 g/149.89 g/mol = 0.011 moles

Since the reaction is in a ratio of 1:1, salicylamide is the limiting reactant and 0.0078 moles of iodosalicylamide is formed.

Hence, theoretical yield of iodosalicylamide = 0.0078 moles × 263.03 g/mol = 2.05 g

Since there is 100% yield, actual yield = theoretical yield = 2.05 g

Answer:

See explanation

Explanation:

Given Einstein's theory of relativity, we have that;

E= mc^2

m= mass of the substance

c= speed of light

For one gram of the substance,

E= 1 ×10^-3 × (3 × 10^8)^2

E = 9 × 10^13 J

For 8.7 g of matter;

E = 8.7 × 10^-3× (3 × 10^8)

E= 7.83 ×10^ 14 J

Answer:

C3H8 + 502+3CO2 + 4H20

Explanation:

In order to get this answer you would have to would balance out the carbons on the products side by multiplying CO2 by 3. The new equation will be 

C3H8 + 02 ----> 3CO2 + H20

Now, that the carbons are balanced, we will look at the hydrogens. We can multiply the number of waters on the product side by 4, to make 4 H20 molecules. This gives both sides of the equation 8 hydrogens. Next we can check our oxygens. There will be 10 oxygens on the products side and 2 on the reactants so to balance these out, we multiply the 02 on the reactants side by 5. 

Answer:

0.20M NaCl is the concentration of the NaCl dilution

Explanation:

A dilution consist on the addition of more solvent in a solution in order to decrease their concentration.

In this problem, the 3.0M NaCl solution is decreasing their concentration 15 times. That is:

3.0M NaCl / 15 =