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3 years ago

Which is most likely to provide the best data on volcanic activity over the last 2000 years?

Chemistry

1 answer:

dimaraw [331]3 years ago

5 0

Answer:

By the time the Vesuvius eruption sputtered to an end the next day, Pompeii was buried under millions of tons of volcanic ash. About 2,000 Pompeiians were dead, but the eruption killed as many as 16,000 people overall. By

the time the Vesuvius eruption sputtered to an end the next day, Pompeii was buried under millions of tons of volcanic ash. About 2,000 Pompeiians were dead, but the eruption killed as many as 16,000 people overall.

Explanation:

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The radioactive isotope of lead, Pb-209, decays at a rate proportional to the amount present at time t and has a half-life of 3.

Marina86 [1]

Answer:

Therefore it will take 7.66 hours for 80% of the lead decay.

Explanation:

The differential equation for decay is

$\frac{dA}{dt}= kA$

$\Rightarrow \frac{dA}{A}=kdt$

Integrating both sides

ln A= kt+c₁

$\Rightarrow A= e^{kt+c_1}$

$\Rightarrow A=Ce^{kt}$ [ $e^{c_1}=C$ ]

The initial condition is A(0)= A₀,

$\therefore A_0=Ce^{0.k}$

$\Rightarrow C=A_0$

$\therefore A=A_0e^{kt}$ .........(1)

Given that the $Pb_{209}$ has half life of 3.3 hours.

For half life $A=\frac12 A_0$ putting this in equation (1)

$\frac12A_0=A_0e^{k\times3.3}$

$\Rightarrow ln(\frac12)= 3.3k$ [taking ln both sides, $ln \ e^a=a$ ]

$\Rightarrow k=\frac{ln \frac12}{3.3}$

⇒k= - 0.21

Now A₀= 1 gram, 80%=0.8

and A= (1-0.8)A₀ = (0.2×1) gram = 0.2 gram

Now putting the value of k,A and A₀in the equation (1)

$\therefore 0.2=1e^{(-0.21)\times t}$

$\Rightarrow e^{-0.21t}=0.2$

$\Rightarrow -0.21t= ln(0. 2)$

$\Rightarrow t= \frac{ln (0.2)}{-0.21}$

⇒ t≈7.66

Therefore it will take 7.66 hours for 80% of the lead decay.

3 0

3 years ago

What volume of chlorine gas (Cl2), measured at STP, can be produced by the decomposition of 73.0g of hydrogen chloride gas (HCl)

gayaneshka [121]

Answer:

Explanation:

2HCl = H₂ + Cl₂

2 mole 1 mole 1 mole

73 gram HCl = 73 / 36.5 = 2 mole of HCl

2 moles of HCl will produce 1 mole of chlorine gas .

At STP , one mole of chlorine gas has volume equal to 22.4 litre .

8 0

3 years ago

Substances made of two or more elements which are not chemically bonded are known as

11111nata11111 [884]

Substances that are not chemically bonded are mixtures.

8 0

3 years ago

The mixture which contains elements only is (a) air (b) brass (c) mineral water (d) seawater

Sholpan [36]

Answer:

So yes! A mixture can contain just elements if those elements are not chemically reactive to one another. Air is a great example of an elemental mixture as it contains nitrogen, oxygen, and argon (along with some other compounds).

Explanation:

hope this helps you :)

4 0

3 years ago

Read 2 more answers

Which type of front occurs when cold air and warm air are next to each other, but are at a standstill?

noname [10]

Occluded font. For sure

8 0

3 years ago