For radioactive decay, we can relate current amount, initial amount, decay constant and time using:
N = No x exp(-λt)
Half-life = ln(2)/λ
λ = ln(2) / 5730
N/No = 80% = 0.8
0.8 = exp( -ln(2)/5730 x t)
t = 1844 years
Answer:
The answer is
<h2>250 g</h2>
Explanation:
The mass of a substance when given the density and volume can be found by using the formula
<h3>mass = Density × volume</h3>
From the question
volume of object = 25 mL
Density = 10 g/mL
The mass of the object is
mass = 25 × 10
We have the final answer as
<h3>250 g</h3>
Hope this helps you
Answer:
c 18.0ml
Explanation:
The average mass of one H2O molecule is 18.02 amu. The number of atoms is an exact number, the number of mole is an exact number; they do not affect the number of significant figures. The average mass of one mole of H2O is 18.02 grams. This is stated: the molar mass of water is 18.02 g/mol.
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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