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Sergio [31]
3 years ago
7

Please Help!

Chemistry
1 answer:
Whitepunk [10]3 years ago
3 0

We can use two equations for this problem.<span>

t1/2 = ln 2 / λ = 0.693 / λ
Where t1/2 is the half-life of the element and λ is decay constant.

20 days = 0.693 / λ 
λ   = 0.693 / 20 days        (1) 

Nt = Nο eΛ(-λt)                (2)

Where Nt is atoms at t time, No is the initial amount of substance, λ is decay constant and t is the time taken.
t = 40 days</span>

<span>No = 200 g

From (1) and (2),
Nt =  200 g eΛ(-(0.693 / 20 days) 40 days)
<span>Nt = 50.01 g</span></span><span>

</span>Hence, 50.01 grams of isotope will remain after 40 days.

<span>
</span>

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Answer:

when an atom, typically a metal, loses an electron or electrons, and becomes a positive ion, or cation. Another atom, typically a non-metal, is able to acquire the electron(s) to become a negative ion, or anion.

Explanation:

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The mass of a proton is approximately equal to
Marrrta [24]
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3 0
3 years ago
Generally speaking, which group would have the lowest electronegativity values in a period?
dezoksy [38]

Answer: Group 1 would have the lowest electronegativity values.

Explanation:

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Generally, across a given period from left to right, electronegativity increases due to increasing nuclear charge and decreasing atomic radius ( or atomic size ). This is because there is a greater tendency for a smaller atom with higher nuclear attraction to attract electrons than a larger atom with a lower nuclear attraction due to the shielding effect of the nuclear attraction by the inner shell electrons on the outermost electrons in the larger atom.

Also, down a particular group, electronegativity generally decreases due to increasing atomic radius/size.

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3 0
3 years ago
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Whats is saturated solution? what happens as a saturated solution cools?
Darina [25.2K]
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8 0
3 years ago
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How many grams of water at 25 C must be mixed in an insulated container with 250 grams of water at 93 C if the final temperature
nydimaria [60]

Answer:

Explanation

Comment

Normally you would just use m*c*delta T. But the c is the same in both cases, so you need just use m*deltaT

Givens

25 degrees

m = ?

T = 25

t = final temp = 75

93 degrees

m = 250

T = 93

t = final temp = 75

Solution

(t - 25)*m = (93 - t) * 250                   Remove the brackets

75*m - 25m = 93*250 -  250*75      Combine the right

m(75 - 25) = 23250 - 250*75

50 m = 23250 - 18750                      Combine

50 m = 4500                                      Divide both sides by 50

50*m/50 = 4500/50

m = 90

Answer: 90 grams are needed.

7 0
2 years ago
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