Can you pick more than one?
Answer:
Half life is the time taken by a radio active isotope to reduce by half of its original amount. Radium-226 has a half life of 1602 years meaning that it would take 1602 years for a mass of radium to reduce by half.
Number of half lives in 9612 years = 9612/1602 = 6 half lives
New mass = Original mass x (1/2)n where n is the number of half lives.
Therefore, New mass= 500 x (1/2)∧6
= 500 x 0.015625
= 7.8125 g
Hence the mass of radium after 9612 years will be 7.8125 grams.
Explanation:
The number of moles of oxygen required to generate 28 moles of water from the reaction is 14 moles
<h3>Balanced equation </h3>
2H₂ + O₂ —> 2H₂O
From the balanced equation above,
2 moles of water were obtained from 1 mole of oxygen
<h3>How to determine the mole of oxygen needed </h3>
From the balanced equation above,
2 moles of water were obtained from 1 mole of oxygen
Therefore,
28 moles of water will be obtained from = 28 / 2 = 14 moles of oxygen
Thus, 14 moles of oxygen are needed for the reaction
Learn more about stoichiometry:
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