Answer:
6.25%
Explanation:
Given data:
Half life of lutetium-117 = 6.75 days
Percentage remaining after 27 days = ?
Solution;
Number of half lives = Time elapsed / half life
Number of half lives = 27 days / 6.75 days
Number of half lives = 4
At time zero = 100%
At first half life = 100%/2 = 50%
At second half life = 50%/2 = 25%
At 3rd half life = 25%/2 = 12.5%
At 4th half life = 12.5%/2 = 6.25%
Answer:
Cu(s) in Cu(NO₃)₂(aq)
Explanation:
The standard reduction potential (E°) is the energy necessary to reduce the atom in a redox reaction. When an atom reduces it gains electrons from other than oxides. As higher is E°, easily it will reduce. The substance that reduces is at the cathode of a cell, where the electrons go to, and the other that oxides are at the anode of the cell.
The standard reduction potentials from Al(s) and Cu(s) are, respectively, -1.66V and +0.15V, so the half-cell of Cu(s) in Cu(NO₃)₂(aq) is the cathode.
Answer:
C. Solids made of molecules
<u>Answer:</u>
Earth's climate has changed naturally over the past 650,000 years, moving in and out of ice ages and warm periods. Changes in climate occur because of alterations in Earth's energy balance, which result from some kind of external factor or "forcing" an environmental factor that influences the climate.
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<u>Explanation:</u>
*Hope this helps*
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Answer:
Ethyl alcohol is soluble in water because <span>ethyl alcohol exhibits dipole-dipole and h-bonding interactions with water.
Explanation:
Ethyl alcohol and water are miscible in each other because both are polar in nature and "Like dissolves Like".
The bond between oxygen and hydrogen atoms, both in alcohol and water are polar in nature and results in intermolecular hydrogen bond interactions between them as hydrogen bonding results when hydrogen atom in one molecule directly attached to highly electronegative atoms like fluorine, oxygen and nitrogen forms interaction with higly electronegative atom of neighbor atom.</span>
