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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:

a.Archaeopteryx

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6 0
2 years ago
The mode of 12, 17, 16, 14, 13, 16, 11, 14,13, 16 is​
RUDIKE [14]

Answer:

<h2>Mean = 14.2</h2><h2>Median = 14</h2><h2>Mode = 16</h2><h2>Range = 6</h2>

Explanation:

__________________________________________________________

<em>Mean = 14.2 or 14</em>

<em>Median = 14</em>

<em>Mode = 16</em>

<em>Range = 6</em>

<em>__________________________________________________________</em>

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8 0
3 years ago
Calculate the energy required to melt 21 g of ice at 0 oC.
vladimir1956 [14]

<u>We are given:</u>

Mass of ice = 21 grams

The ice is already at 0°c, the temperature at which it melts to form water

Molar heat of fusion of Ice = 6.02 kJ/mol

<u>Finding the energy required:</u>

<u>Number of moles of Ice: </u>

Molar mass of water = 18 g/mol

Number of moles = given mass/ molar mass

Number of moles = 21 / 18 = 7/6 moles

<u>Energy required to melt the given amount of ice:</u>

Energy = number of moles * molar heat of fusion

Energy = (7/6) * (6.02)

Energy = 7.02 kJ OR 7020 joules

7 0
3 years ago
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KiRa [710]

Answer:

6605.3900 g/

Explanation:

3 0
3 years ago
Calculate the number of C atoms in 0.190 mole C6H14O.<br> can anyone help me on this one?
likoan [24]
In 0.190 mole of C6H14O, there is 0.190*6 (number of C in one molecule) = 1.140 mole of C atoms. The total number of C atoms = 1.14 * 6*10^{23} (atoms of C in one mole) = 6.84*10^{23} atoms. 
8 0
3 years ago
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