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Nimfa-mama [501]
2 years ago
6

The isotope carbon-14 decays over time into nitrogen-14 with a half-life of 5,730 years. Suppose that you find a fossil that con

tains 1.25 grams of carbon-14 and 3.75 grams of nitrogen-14. How old is the fossil
Chemistry
1 answer:
KATRIN_1 [288]2 years ago
3 0

Answer:

11460 years

Explanation:

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

t1/2 = half life of the carbon

t = age of the fossil

No= amount of radioactive material originally present

N= amount of radioactive material present at time=t

No= mass of carbon + nitrogen = 5g

0.693/5730 = 2.303/t log (5/1.25)

1.21 ×10^-4 = 1.3866/t

t= 1.3866/1.21 ×10^-4

t= 11460 years

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C. Another radioisotope of americium exists which has an atomic mass of 242.
ollegr [7]

Answer:

1 g  

Explanation:

The half-life of Am-242 (16 h) is the time it takes for half of it to disappear.

We can make a table of the mass left after each half-life.

\begin{array}{cccc}\textbf{No. of} & & \textbf{Percent} & \textbf{Mass}\\\textbf{Half-lives} & \textbf{Time/h} & \textbf{Remaining} & \textbf{Remaining/g}\\0& 0 & 100 & 8\\1 & 16 &50 & 4\\2 & 32 & 25 & 2\\3 & 48 & 12.5 & 1\\4 & 64 & 6.25 & 0.5\\\end{array}

The mass remaining after 48 h  is 1 g.

7 0
3 years ago
Which chemical formula represents both an element and a molecule?
victus00 [196]

Answer:

Explanation:

element - a basic substance that can't be simplified (hydrogen, oxygen, gold, etc...) molecule - two or more atoms that are chemically joined together (H2, O2, H2O, C6H12O6, etc...) compound - a substance that contains more than one element (H2O, C6H12O6, etc...)

5 0
2 years ago
Can Hydrocyanic acid be a Lewis Acid? What about a Lewis Base?
FinnZ [79.3K]

HCN is a Bronsted acid; it can dissociate into H+ and CN-. And H+ is a Lewis acid because it accepts election pairs. ... In order for H+ and CN- to be formed, Hydrogen in HCN donates its electrons to Carbon. So in this sense, Hydrogen is the lewis base and Carbon is the lewis acid.

8 0
3 years ago
HELP!!!!!What is the molar mass of a gas which has a density of .249 g/L at 20.0 degrees Celsius and a pressure of .95 atm?
fgiga [73]

Answer:

6.31g/mol

Explanation:

Using the ideal gas equation;

PV = nRT

Where;

P = pressure (atm)

V = volume (L)

n = number of moles (mol)

R = gas law constant (0.0821 Latm/molK)

T = temperature (K)

Mole (n) = mass (m)/molar mass (Mm)

* Mm = m/n

Also, density (p) = mass (m) ÷ volume (V)

PV = nRT

Since n = M/Mm

PV = M/Mm. RT

PV × Mm = m × RT

Divide both sides by V

P × Mm = m/V × RT

Since p = m/V

P × Mm = p × RT

Mm = p × RT/P

Mm = 0.249 × 0.0821 × 293/0.95

Mm = 5.989 ÷ 0.95

Mm = 6.31g/mol

7 0
3 years ago
What did sewage treatment in Ancient Rome and 19th century London have in common? How effective was this strategy and why?
anygoal [31]

Yea pretty much

Explanation:

4 0
3 years ago
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