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alisha [4.7K]
3 years ago
11

After 15 minutes, 30 g of a sample of polonium-218 remain unchanged. If the original sample had a mass of 960 g, what is the hal

f-life of polonium-218? Suppose you want to separate the leaves, acorns, and twigs from a pile of soil. Filtration and distillation are two processes of separating mixtures. Explain which process you would use and why.
Chemistry
1 answer:
Keith_Richards [23]3 years ago
5 0
Q1. The answer is 3 minutes.

Let's first calculate the remaining amount in percent:
If 960g is 100 percent (starting amount), 30 g is how many percents:
960 g : 100% = 30 g : x
x = 30 g * 100% / 960 g = 3.125% = 0.03125

Now, using the formula to calculate the number of half-lives:
(1/2)ⁿ = x,
where
x is the remaining amount: x = 0.03125
n is the number of half-lives
1/2 stands for half-life.

(1/2)ⁿ = 0.03125
⇒ n*log(1/2) = log(0.03125) 
    n = log(0.03125)/log(1/2) = log(0.03125)/log(0.5) = -1.505/-0.301 ≈ 5

The number of half-lives is 5.
Now, <span>the number of half-lives (n) is a quotient of total time elapsed (T) and length of half-life (L):
n = T/L
We know:
n = 5
T = 15 min
L = ?

Thus
L = T/n
L = 15 min/5 = 3 minutes

Q2. Filtration should be chosen.
Filtration and distillation are used to separate mixtures - filtration for the separation of heterogeneous mixtures and </span>distillation for the separation of homogeneous mixtures. Imagine that your pile of soil is a mixture. It consists of different components (the leaves, acorns, twigs), so it is the heterogeneous mixture. Therefore, to separate the leaves, acorns, twigs you will use filtration.
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<u>Answer:</u> The value of K_p for the reaction at 690 K is 0.05

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We are given:

Initial pressure of COCl_2 = 1.0 atm

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                  COCl_2(g)\rightleftharpoons CO(g)+Cl_2(g)

Initial:            1                    -         -

At eqllm:       1-x                 x        x

We are given:

Total pressure at equilibrium = [(1 - x) + x+ x]

So, the equation becomes:

[(1 - x) + x+ x]=1.2\\\\x=0.2atm

The expression for K_p for above equation follows:

K_p=\frac{p_{CO}\times p_{Cl_2}}{p_{COCl_2}}

p_{CO}=0.2atm\\p_{Cl_2}=0.2atm\\p_{COCl_2}=(1-0.2)=0.8atm

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K_p=\frac{0.2\times 0.2}{0.8}\\\\K_p=0.05

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3 years ago
How is sodium extracted from is ore?
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Answer:

Sodium is extracted from it's ore by electrolysis of fused sodium chloride.

Explanation:

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If 0.50 mol/L of butane is added to the original equilibrium mixture and the system shifts to a new equilibrium position, what i
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Consider the isomerization of butane with equilibrium constant is 2.5 .The system is originally at equilibrium with :

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The equilibrium concentration of each gas:

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Explanation:

Butane  ⇄  Isobutane

At equilibrium

1.0 M               2.5 M

After addition of 0.50 M of butane:

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