The amount of sample that is left after a certain period of time, given the half-life, h, can be calculated through the equation.
A(t) = A(o) (1/2)^(t/d)
where t is the certain period of time. Substituting the known values,
A(t) = (20 mg)(1/2)^(85.80/14.30)
Solving,
A(t) = 0.3125 mg
Hence, the answer is 0.3125 mg.
Answer:
boron (B), silicon (Si), germanium (Ge), arsenic (As), antimony (Sb), tellurium (Te), polonium (Po) and astatine (At)
Explanation:
metalloids are elements that are in between the metals and nonmetals. they are in between because they have properties of both metals and nonmetals.
you can search "metalloids on the periodic table" and go to images to see what i mean :)
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Answer:</h2>
ZINC
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Explanation:</h2>
<em>To identify the element based on the informartion given, we have to find the molar mass since this mass is unique to each element.</em>
Molar mass = mass ÷ moles
<em>We already know the mass based on the question, as such we now need to find the # of moles.</em>
Since 1 mole contains 6.02214 × 10²³ atoms
then let x moles contain 4.19 × 10²³ atoms <em>(given in the question)</em>
<em> </em><em> </em> ⇒ x = (4.19 × 10²³ atoms × 1 mol) ÷ 6.02214 × 10²³ atoms
x = 0.69577 mol
<em>Now that we have the moles we can substitute it into the molar mass equation and solve for the molar mass.</em>
⇒ molar mass = 45.6 g ÷ 0.69577 mol
⇒ molar mass ≈ 65.54 g/mol
This molar mass is closest to that of ZINC.
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