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Ilia_Sergeevich [38]
2 years ago
12

A fossil is found to have a 14 C 14C level of 70.0 70.0 % compared to living organisms. How old is the fossil?

Chemistry
1 answer:
natulia [17]2 years ago
8 0

Answer:

The age of the fossil be 2.1987\times 10^{4} years.

Explanation:

Formula used :

N=N_o\times e^{-\lambda t}\\\\\lambda =\frac{0.693}{t_{\frac{1}{2}}}

where,

N_o = initial mass of isotope  C-14 = x

N = mass of the parent isotope left after the time, (t)  = 70.0% of x=0.07x

t_{\frac{1}{2}} = half life of the isotope  C-14 = 5730 years

\lambda = rate constant

Let the age of the fossil be t.

Now put all the given values in this formula, we get  t :

0.07x=x\times e^{-(\frac{0.693}{5730 years})\times t}

t=2.1987\times 10^{4} years

The age of the fossil be 2.1987\times 10^{4} years.

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What is net ionic equation borax hydrolysis?
deff fn [24]
The net ionic equation of borax hydrolysis would be:

 <span>Na2B4O7 + 7H2O-----------------> 2 NaOH + 4 H3BO3
</span>
Wherein 2 moles of sodium hydroxide and 4 moles of boric acid are produced by the hydrolysis.
I hope my answer has come to your help. Thank you for posting your question here in Brainly. We hope to answer more of your questions and inquiries soon. Have a nice day ahead!
7 0
2 years ago
The pKs of succinic acid are 4.21 and 5.64. How many grams of monosodium succinate (FW = 140 g/mol) and disodium succinate (FW =
Varvara68 [4.7K]

Answer:

9.744g of monosodium succinate.

4.925g of disodium succinate.

Explanation:

To find pH of the buffer produced by the mixture of monosodium succinate-Disodium succinate is obtained from H-H equation:

pH = pKa + log ([Na₂Suc] / [NaHSuc])

As you want a pH of 5.28 and pKa is 5.64:

5.28 = 5.64 + log ([Na₂Suc] / [NaHSuc])

-0.36 = log ([Na₂Suc] / [NaHSuc])

0.4365 = ([Na₂Suc] / [NaHSuc]) <em>(1)</em>

<em />

As total concentration of the buffer is 100mM = 0.100M:

0.100M = [Na₂Suc] + [NaHSuc] <em>(2)</em>

Replacing (2) in (1):

0.4365 = (0.100M - [NaHSuc] / [NaHSuc])

0.4365 = (0.100M - [NaHSuc] / [NaHSuc])

0.4365 [NaHSuc] = 0.100M - [NaHSuc]

1.4365 [NaHSuc] = 0.100M

[NaHSuc] = 0.0696M

And:

[Na₂Suc] = 0.0304M

As volume of the buffer is 1L:

[NaHSuc] = 0.0696 moles

[Na₂Suc] = 0.0304 moles

Using molar mass of both substances:

Mass of monosodium succinate:

0.0696moles * (140g / 1mol) =<em> 9.744g of monosodium succinate.</em>

Mass of disodium succinate:

0.0304moles * (162g / 1mol) =<em> 4.925g of disodium succinate.</em>

<em></em>

5 0
2 years ago
How many liters of radon gas would be in 3.43 moles at room temperature and pressure (293 K and 100 kPa)?
OLga [1]

Using ideal gas equation,

P\times V=n\times R\times T

Here,

P denotes pressure

V denotes volume

n denotes number of moles of gas

R denotes gas constant

T denotes temperature

The values at STP will be:

P=100 kPa

T=293 K

R=8.314472 L kPa K⁻¹ mol⁻¹

Number of moles of gas=3.43 mole

Putting all the values in the above equation,

V=\frac{3.43\times 8.314\times 293}{100}

V=83.55 L

So the volume will be 83.55 L.

83.55 L of radon gas would be in 3.43 moles at room temperature and pressure (293 K and 100 kPa).

4 0
2 years ago
Why is radioactive dating important when approximating the age of earth?
Furkat [3]

Answer:

So, we rely on radiometric dating to calculate their ages. Radiometric dating, or radioactive dating as it is sometimes called, is a method used to date rocks and other objects based on the known decay rate of radioactive isotopes.

Explanation:

radiometric dating is a very accurate way to date the Earth.We know it is accurate because radiometric dating is based on the radioactive decay of unstable isotopes. When an unstable Uranium (U) isotope decays, it turns into an isotope of the element Lead (Pb).

6 0
2 years ago
Read 2 more answers
Which will not appear in the equilibrium constant expression for the reaction below?
n200080 [17]

Answer:

[C] carbon solid

Explanation:

Pure solids and liquids are never included in the equilibrium constant expression because they do not affect the reactant amount at equilibrium in the reaction, thus since your equation has [C] as solid it will not be part of the equlibrium equation.

5 0
2 years ago
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