Half life is the time taken by a radioactive isotope to decay by half its original mass. In this case, the halflife of the radioactive isotope is 5000 years.
Initially the mass is 100 %; thus the mass that will be left will be given by;
New mass = Original mass × (1/2)^n where n is the number of half lives;
n = 10000/5000 = 2
New mass = 100% ×(1/2)^2
= 100 % × 1/4
= 25%
Therefore; the mass left after 10000 years is 25% or 1/4 of the original mass.
Answer:
<h2>2.408 × 10²¹ is the correct answer!!</h2>
The answer is: [B]: "ionic salt" .
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Note: There is no "sharing of electrons" among the elements in this compound; so this compound in NOT a "covalent molecule".
However, there is ionic bonding: Cu²⁺ and Cl⁻ ; to form: "CuCl₂" .
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The volume occupied by 0.102 mole of the helium gas is 2.69 L
<h3>Data obtained from the question</h3>
The following data were obtained from the question:
- Number of mole (n) = 0.102 moles
- Pressure (P) = 0.95 atm
- Temperature (T) = 305 K
- Gas constant (R) = 0.0821 atm.L/Kmol
- Volume (V) =?
<h3>How to determine the volume </h3>
The volume of the gas can be obtained by using the ideal gas equation as illustrated below:
PV = nRT
Divide both sides by P
V = nRT / P
V = (0.102 × 0.0821 × 305) / 0.95
V = 2.69 L
Thus, the volume of the gas is 2.69 L
Learn more about ideal gas equation:
brainly.com/question/4147359
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